MoPar rated the hemi as 425 HP @ 5000 rpm. What they neglected to say was that the dyno pulls went to 6000 rpm, and at 6000 revs, the engine put out 495 hp. There is a content provider on TH-cam, "Nick's Garage" and he has a weekly show specializing in MoPars. Particularly he works on a ;lot of 440s and hemis, although other engines come into the shop as well. In one of his shows he re-created a stock spec 426 hemi, totally stock except for a .030 overbore. He then ran it on his SuperFlow 902 dyno, and that's what it put out. Sure enough, at 5000 rpm it was 425 hp, but at 6000 the totally stock hemi put out 495 hp.
@@moparconnection Were you running solid lifters or hydraulic lifters and if you were running solids were they set at .028 intake cold and .032 exhaust cold? Nick tightens the lash up on his until they "sound right"! The factory spec sheet the dealer gave me said .028 intake cold and .032 exhaust cold and .030 intake hot and .030 exhaust hot, didn't say a word about decibels, and they sure did clatter.
@@matrox Funny how many people get different hp figures on the dyno with the 426 hemi, most get 525hp at 6000rpm and power nation got 820hp with a blueprinted 426 hemi, who do you believe? I had a 426 hemi and never found any competition on the street and yeh there were plenty of muscle cars around and many were anything but stock and raced at the local strip and all top fuel dragsters and funny cars run Chrysler Hemis, just a fact of life. All I have to say is having power and knowing how to use it sure helps and spinning isn't winning, always left at 1800 rpm and never power shifted. And let's not forget that the 426 hemi and fords 429 hemi were required to run restrictor plates so the GM cars could keep up and that is another fact of life.
Compression would play a part. This had 9.6:1, Nick's was in the factory range. They say about 5% more power per point of compression. If this had 10.25:1 then that would add about 15 more HP, narrowing the gap a bit. Nicks may have been 10.5:1 but I could be wrong. The 632hp 505 dual plane single quad Hemi he dynoed was what blew me away.
He was not running a water pump or an alternator, and his was closer if not at the advertised stock 10.25:1 compression ratio. The water pump and alternator parasitic drag plus the 3/4 point loss in compression will account for the 37 HP difference.
Back in the late ‘80s, we pulled a hemi out of a wrecked Plymouth with a little over a hundred thousand on the odometer. I put it straight on the dyno before pulling it apart to rebuild it. It made 535 horsepower at 6 thousand RPM and held 60 lbs. of oil pressure. I almost didn’t want to pull it apart but it had a leaky head gasket and a broken ring so it smoked like crazy. .30 over on the bore, a nice cam, fresh bearings, and a little carb jetting, it made just under 700 hp. Still running today, never opened since building it. Good motor.
Impressive story !! ......Without any engine build/tune data, inferences to 6 digit odometer #'s & smoke "hurt" runnin condition, seems youall found the rare 20yr old, wore out 1 cylinder down "unicorn" hemi still producing new Factory built super stock race "Package" engine power numbers Especially after the relatively simple 030 over & bearings fresh-up, "nice cam" & carb tweaks & wakin up crankin over the top dyno #'s requiring an impressive Torque curve.....
@@tomstrum6259 the 426 was so underrated by the factory, it’s almost shameful. Insurance companies were starting to crack down on covering muscle cars was the reasons given, but I don’t know. As for the car it came out of, I watched the odometer roll over on a road trip before it was wrecked because it belonged to my cousin who bought it new. A set of headers, a jet change in the factory carbs, and timing right off the factory floor bumped the hp numbers by almost 3 figures alone. The Chevy LS6 made similar numbers with the same minor mods, not a fan of Chevy, but I built one for my dad to replace the wore out 396 in his Chevelle that he bought when he got home from Vietnam. I’m not claiming to be some expert or guru, but I have been building drag engines since 1984, mostly for myself and close friends.
To each their own "memories" I spose.....Chrysler advertised the production Street hemi power & torque ratings very accurately & honestly....425 actual on average, some better some less.....Whatever winds yo crank man.....
@@tomstrum6259 Is that why power nation blueprinter a stock 426 hemi and got 820 hp with it on a dyno? Guess you should contact those who did the testing and tell them they had a bad dyno, huh?
I have a numbers matching beautiful AAR Cuda and I simply cannot drive it. It is really a shame. These cars are worth way too much to drive anymore. I like to call it a 3600 pound paperweight. I will be selling it soon and just driving around my 1971 340 Duster. It isn’t worth that much.
Thanks for your approach to this Hemi build. The HP of these engines are all over the place. This is a good approach at what might have been delivered to the public in the 70’s. The Hemi is the most legendary engine offered in the 60’s and 70’ s and that is without a doubt. You either wanted a Hemi or you wanted to beat a Hemi. It was the litmus test on the street. Wether it lived up to the hype or not is not the answer. As legends go it got bigger and bigger in street lore. And as the top engine used in top fuel it also backed up the hype. Yes an LS6 454 is legendary too. As is the 427 Ford. Even small blocks have status. But the Hemi sits on top because of the hype. I have never owned a 2nd Gen. Hemi but I drove one one time in 79. A 66 Hemi Charger automatic. And I only got into it a little bit. But the torque was without question evident to me. If you wanted a Hemi to rule your streets, it took more money and wrenching. But it was an awesome starting package. Headers and a high lift cam would give back startlingly results. But tuning the distributor and carbs was a must after such modifications. The Hemi was a detuned race engine. And you had to return it back to what it needed to be with the right parts. You could go full bore and add 12:1 pistons and oil mods too. It was just what you could afford to do. Same with the other big blocks available at the time. It was definitely a different world in those days. And I miss them. Simpler times. Thanks for the video.
@@moparconnection I know. That is why I said your approach was as it would have been delivered in the 70’s stock factory car. Or my meaning was such. I bet that 572 is a beast. Now that is legendary.
I would argue it having the top "legendary status". I would say the ford cammer has more legendary status. What people's actual opinion is of the engine might vary. But as far as legendary? My vote would be the cammer. Becouse who dous anybody know that actually has or had a cammer?? In a rare moment one might see a hemi. But most never see a cammer in a liftime.
Yes I’m a Ford guy. I love the camera however it was never put in our car. Chrysler somehow offered from 66 to 71 like you say it was incredible time in history. I am 61 years old. I miss those days cruising Whittier Boulevard I graduated 81 back then you could buy a street hemi for around 04 to $5000 believe it or not. I remember gas being way under a dollar a gallon.😢
@stevo196two9 ur right, there is no Vin code that would indicate a factory cammer car. It was made available though as a "high rev, race ready, replacment engine" for your new Ford car. A over the counter ford replacment part.
Thx for truthful informative video...Your Dyno performance numbers seem just about right..With 1000 miles, my factory pure stock '70 hemi cuda Automatic click off 13.1's @ 107 all summer day long with full gas tank @ 4000 lbs.....Carbs never Touched, 4.10 Dana, 35° timing ....
Correct me if I’m wrong, but it’s my understanding that the 70-71 Hemis were hydraulic cammed. I love to see the difference of the 70s Hemi vs early models with solid lifters.
Engine Masters tested the 426 Hemi vs a 440 and it turned out the hemi was great for….high sustained rpm but the 440 made killer torque for drag racing
@@DavidPhillips-rs5dq yeah and if a 318 was 800 cubes... it would make more power. BUt guess what.... it isn't Don't blame the OP because mopar never put any cubes behind the hemi heads.
@@DavidPhillips-rs5dqNo that’s not the reason. The Hemi heads are top end flow and suffer a bit down low. It could be a 440 Hemi and still make less torque than a 440
Awesome video. 👍 My Mopar is my 1968 Barracuda fastback powered by a 400 based 512 stroker featuring Trick Flow 240 heads and a hydraulic roller cam with 254 duration @.050 with 618 lift, backed by an A833 4 speed manual. 👍
People dont realize the StreetHemis were detuned race motors, which dont work real well on the street in daily use. A well tuned stock 440/6 will out run a Hemi half the time. We ran a 64 RaceHemi with aluminum heads and a Hilborn injector system in a steel 37 Willys coupe and it put out way more than 650hp on a basically stock motor (no wild cam or exotic stuff other than the injector and magneto)
Oh yeah, worse than that. Street Hemis weighed 812lbs, had lazy hydraulic camshafts and sloppy, misaligned valvetrain. Nothing about them were high performance.
Joking aside, I do have just a bit of Machine shop experience under my belt, growing up in Flint, Michigan at Precision auto & Machine shop. I've never seen a pachyderm on the dyno that put out less than 435 h/p, most are up there around 450-480, Mopar really built a beast when they built that HEMI. Thanks for sharing this with all of us, I'm sure everyone else enjoyed it as much if not more than I did.
They all heavily underrated their engines. I have a theory that since they sold the cars all over the US. They needed to make sure even in say Denver the engines would put out their advertised HP. Today our advertising laws are extremely lax. You can tell someone your polonium tea cures cancer and as long as no "reasonable person" would fall for your advertising. Well you can't be sued for false advertising. But our advertising laws weren't always like that.
A friend of mine had a '70 GTX 426, convertible, auto on the column. If it was only 425 hp, it was a STRONG 425! He never got beat by anyone locally on the street. It was a beast. I don't know why you didn't do a pull at 6,000. The '70 GTX shifted at 6200 if just left in "D" to do it's own thing.
Interesting. I have a 426 in my '68 charger ( not original ) Its a late '66 casting. The engine was built by Al Lee, of Lee brothers ( ' 68 hemi SS barracuda fame ) I talked to him after installing the engine and he told me he had punched it out 60 thousand and installed the correct factory mechanical cam. Other than electronic ignition and a gorgeous 3" TTI exhaust, its totally stock right down to the Carter carbs. Al told me, from his experience, it should be just a little over 500 at the flywheel. This summer i plan on taking her down the 1/4 to see.
I remember when Jim Drain from FL went out to see the 426 he had Dick Landy build, it made 525 HP and Jim was mad about it as it was going in his 1967 GTX Hemi 4 speed that was a pretty much an NOS car and the engine was supposed to be a stock rebuild. Dick just told Jim to calm down and when the Hemi was properly blueprinted, it would make these kind of numbers.
Thanks! Certainly no other engines could match the street hemi in 1966 when it came out and they would make more power in the upper rpm range than anything else.
I liked the honesty of this pull. From what a stock Hemi was doing in the day. About 450-460 is quite good. Many dynos are kind of “ happy “ and they have caveats. This is straight up.
This doesn't sound right, but according to my vintage Motors Manual (early model edition 1968-1974), only the 1971 426 came with hydraulic lifters. All other 426's were solid lifters clearanced at .028 intake and .032 exhaust (cold). The hydraulic cammed cars had adjustable rockers and a spec. for that.
The 70-71 Hemi’s all had hydraulic cams, the specs were the same as the 68-69 series 2 cam, just hydraulic, and they still retained the adjustable rockers, but shorter push rods. Just look in any 70-71 service manual for documentation.
@@moparconnection He's correct, hydraulic lifters for Hemis starting in 1970. It's called out in the '1970 Challenger Lineup' dealer binder, and again in the 1970 Plymouth Rapid Transit System advertisement, page 15. I'm sure it is also called out in the factory service manuals, but I don't have a '70 on hand. No solid lifter E-bodies.
Yeah it’s super disappointing but given how expensive and frankly, difficult the Hemis were to machine, racers and builders found all sorts of inconsistencies.
I traded a guy a boat for a '70 'Cuda w/ a 383 and one of the factory pistol-grip shifters, that I later found a Hemi for, along w/ one of the cross-ram intake systems Mopar developed specifically for these engines and high performance applications. What a screamer! With two Carter 850 CFM carbs it ran just over 10 second 1/4 miles. My favorite exercise was cruising at 3K-4K RPMs in second gear just to hear that engine sing. Back when I thought everything was replaceable, because I sold that jewel - its replaceable, right? smh
I have a 1969 Car Craft magazine issue in which they drag race test a 69 Roadrunner 440 6 pack automatic. They fiddled around with it and got some decent times out of it with slicks. As evening approached they realized the exhaust manifolds were glowing red hot after each pass and obviously a set of headers were needed. I've seen a true survivor Hemi Roadrunner that was absolutely bone stock but most people that bought a Hemi car for performance NEVER left it stock. A set of correctly made headers that match the stock cam and a correctly recurved factor distributor and the factory carbs rejeted by someone who knows what they are doing is worth 65 horsepower minimum so who gives a flip what the engine would do off the showroom floor ??
Had a 1967 Satellite with the 426 Hemi 4 speed dana 60 with 3.54 gears with a track lock. I believe the compression was 10.25:1 with a slightly smaller cam then the 68&69 Hemi's. First thing I had to do was adjust the valve lash, .028 intake and .032 exhaust cold, oh my did those lifters clatter, everyone who got in the car told me there was something wrong with the engine. I know for a fact that many dealers would set them at zero lash because people would not buy them for that reason. I made two changes to the engine, one; a set of chrome moly pushrods and two; added a braided copper wire between the stationary plate and the breaker plate to eliminate ignition breakup from 5500rpm to 7000rpm. And for whatever it is worth yes it would turn 7000rpm in every gear and no you didn't hold it there in any gear so as not to grenade it and you didn't power shift it into any gear unless you wanted to do a donut. It was on H70/14 Dunlap bias ply tires so there wasn't a lot of rubber on the road. Don't understand why people complain about the Hemi being a dog on the street unless they just didn't know how to drive it. And I have talked to a few former Hemi owners and no they didn't. And hey even Nick from Nick's garage tells me he reduces the valve lash until it sounds right to him!!!!!! Gee I wonder if that's why they had a reputation for valve train wear, DUH!
Yea it was and I still miss it. I have a 66 Satellite and a ton of 440's, 400's, 383's, 360's, 340's,318's, but no Hemi. Now if I could just be lucky enough to hit the lottery! I am guessing you know enough to run a remote oil filter and pipe one return into the passenger's side at the rear of the block where the sending unit goes, this will prevent oil starvation on 6,7&8 rod bearings at high rpm and you know to keep your engine loaded, pulling, when winding it so as not to blow it. No better way to blow an engine than to wind an engine with no load on it, another reason why I never power shifted.@@moparconnection
Don't know what to tell you, but the distributor in my 67 did not have one until I installed one, maybe someone at the factory figured out the same thing I did and yours was a 70 and mine was a 67 and as we all know the factories were always making changes. You're making a big assumption that because your 1970 distributor had one that my 1967 distributor had one.@@budlanctot3060
@@stephenwest798The Hemi will also have piston slap noise when cold too. Did you do the lash the same way us HyperPak Slant blokes do? - While It's Running 😊 Gets perfect lash at operational temperatures, solid cam and lifters (like the 273's had in the 60's) on the stock Slant always sounds like a sewing machine running somewhere under the hood. But once it's right, throttle response is crisp, and the emissions go way down, same with fuel usage out on the freeway. The valve train with correct lash and replacing the stock phenolic cam gear and morse chain with a roller chain and gears on the Slants and the V8's, the valve timing stays perfect, the ignition timing stays perfect, the wear goes away to the point you can run the Lean Burn computer and have it be reliable. Check the lash every couple of filter changes, these things just keep going.
My buddy who is working on my 70 442 is a huge mopar guy. He has some really cool cars trucks ect.. I think its a replica but 1 truck he has is The Little Red Wagon he takes it to Cordova for some show every year
You mentioned this was rebuilt from a bear body. That would have been very difficult, because I rebuilt one from a hippopotamus body and that thing was a monster. So, hats off to you.
One of the guys from Holman Moody said that the 427 Fords that were sent to their shop to be prepped for NASCAR came to them at about 510 hp. So they pretty much use the parts. The Ford gave them and just blueprinted of the engine. The street version that was in the cobra put out about the same as the hemi. 425 hp. I suspect the Chevy was about the same because we know the “special“ engines were producing the same 500 hp as the Ford race engine was. For the GT40 and other endurance racing they tuned all of those engines a little bit.
A couple things.... wasn't the street hemi a hydraulic lifter engine? Also, blue printed engine should make more power than an off-the-line one. Where the hemi really excelles.... great lower rpm lift and stout bottom end - make for a really nice and reliable forced induction engine.
NO !! ....All 1966 (First yr hemi option) thru 1969 Street hemis came with Solid lifter flat tappet cam with only 1 slight cam upgrade during that 3 yr span....Hydraulic Only cam in '70--71 yrs....
I seem to recall the stock compression ratio on the OEM spec 426 HEMI was 10.25 to 1. I think yours is a bit low. That's a really nice engine, and represents the legend of the street HEMI quite well. Sounds healthy.
So, 438 CID, but compression a full point lower than the Street Hemi. Those deviations may offset and get you close, but I'd still like to see what real factory-spec hemis made. I suspect that will keep getting harder to find as years go by.
Not quite. While Chrysler advertised 10.25:1 many engine builders found their street Hemis had far below that compression ratio. The compression height of our pistons, rod length and crank all remained identical to stock. The block wasn’t decked and we compensated for the decked heads with a thicker gasket. It came out to 9.6:1.
450/480 sounds more like reality. Too many guys saying they made sooo much more like 100, lol. That torque curve kicks butt for any st car. So many focus on a hp number but totally ignore the tq which is where it makes the beans.
@@moparconnection It was always rated in octane because of the higher tetraethyl lead content...Back then 110 was normal....And aviation fuel was 125/145 octane...
I owned a 440 6 pack cuda with only headers and a 4:10 Dana - 4 speed . Car was consistently 11.8 to 12.0 in the 1/4. Not too many Hemis were tuned properly to beat it "
I loved building my uncles 68 gen 2 barracuda. The hemi 426 we went mid way on build ( first start up vid on my TH-cam channel) Dean @ big AL'S toy box and AL the owner assembled and dyno'd the 66 block and performance parts . Pulled 650 hp / 750ftlb on 93 octane
I've heard many made around 450hp at the crank. Some made close to 500 HP at the crank. My cousin saw one with headers and slight turning made close to 600 HP and went 10.9 in the quarter mile ( with slicks)
We are talkin Chrysler factory Stock production line built & delivered cars ?? ....Everyone gots the passed down "Cuz" car "story" I 'spose.....'Cept in yo dreams, ...No Chrysler production factory cammed '60's--'70's big block (Street hemi included) lead sled lame cammed & hardly any compression muscle car got near Slick tires 11's or 10's 1/4mi time slips....Whatcha smokin ??
Would have been far better off pulling out useless mass with modern pistons and rods, and not having to further sodomize the crankshaft welding mass back into it. Could have really been money ahead going to 2.200 BBC rods on the crank throws. But I get that it's fun to see what the old junk would do "back when" and it's a cool car, with a resto build engine.
I thought your team did a great representation of a stock 426. QUESTION: Im curious of what the gap was from the top on the piston and the block deck ?
The 1970-71 Street Hemi had a hydraulic cam with same timing specs as the 69 solid cam...so they say. You could not find a correct hydraulic cam? My brother still has his 1970 Hemicuda he ordered new. I have the original factory hyd. cam which had 10,000 miles on it. I set it up in my lathe and like you checked out the numbers. I got 228 degrees duration at .050 and a gross of 284. Lobe lifts at .309 to .311 I made a dummy lifter of the correct diameter of a stock Hemi lifter and dial indicator off of that.
Back in the day the 426 was no joke especially when you had high performance 3 duce 4 speed the I was around in 75 had never been rebuilt and turned 6000 rpm with no complaints.
I remember a magazine article back in the day where the author after driving a stock 426 Hemi car opined that he thought it was closer to 500 HP than it was to 425 HP.
Everyone know that most of these engines had more power than advertised. BUT you have fitted it ro a tent car,, they flex badly. Then fitted with the tyres that killed hundreds,, Badday Polyglass. So you have a 140mph car with a 70mph chassis on 20mph tyres.
Basically you lowered the compression with those super thick gaskets by at least .5 leaving you at 9.75: 1 or lower and reducing factory power output by at least 25hp.
@@moparconnection Of course. DCR is always lower than SCR and DCR is fixed unless you installed VCT on that hemi, Right? The fact is that you lowered the SCR by using monstrously thick head gaskets thus losing over 25hp.
Always loved these old engines. I will say this, though: "From the factory", it wouldn't make this same power level. You have the additional bore, of course which couldn't be helped....but it does add power. 8-10hp, easily. In the big picture, that isn't a lot but in this case when we're talking "what did it do off the showroom floor?", it matters. Then the heads...no way they don't have a better valve job, since they were on a drag motor, right? That helps. And I'm sure it's balanced. So while it's about as close are you're going to get these days, I'd say an actual "out of the box" Hemi would be down a bit from where this one is. Still gets us in the ballpark, though.
You can see clearly from the chart that after 5500 rpm, the power dropped off. That means that in this configuration, this engine made 452. 7 hp tops. It is only turning a water pump and an alternator with an open headers exhaust, which means that this is basically gross horsepower. Modern Ford Mustang 5.0 liter/302 cubic inch DOHC 32 valve engines make 480 hp at the crank but that is NET horsepower. These old engines are fascinating, but they aren't what people think they are; Modern Hemi's would use one of these "elephants" as a breakfast food....
Another thing the big 3 did, was to leave off things like alternator, water pump and mufflers or anything that would sap horsepower. We have to mention also, that the horsepower rating system went from gross horsepower to S.A.E. net horsepower in 1972. This meant a certain standard was adhered to, like mufflers, water pump and the room at 70° Fahrenheit. The year prior (1971) saw the first round of emissions phased in. While none of this affected a 1970 engine, we no longer live in the year 1970 and horsepower today is measured in S.A.E. net. I find it amusing that gross horsepower is still used in some areas, like rating lawn mowers or farm equipment.
Mopar Connection Magazine....In fact, the only way to build a ''numbers matching motor'' for this car was to rebuild the 318 original motor...That is the only way...any other motor won't match...unless you punch new numbers on the replacement motor that you stick in it...
Nice video Kevin. Would have been nice to seen some of the machine work and parts as well as the processes. Should be a great engine. Have a great day.
The std Available factory options should've Included something similar to the "Max Wedge" X-ram intake Holleys & properly Cam'd & High domed factory Race version....550hp flywheel Easy.... Would've been a Total game changer Max perf street car....but they Didn't.....
There was no "Direct Connection" dealer Participating support during '66 thru '71 available until 1974 ....No Factory/dealer help at all for Original Street owners & Typical Chrysler dealers had No knowledge or showroom Brochures on the very rare limited Production, race Only drag package car componets so You were on your Own in middle of "Nowhere USA" & No dealer support.....Unlike the extreme limited production, Factory S/S race car package Hemi with Deep plunge cut valve Relief pistons, All street hemi engines came with Extremely tight valve relief low compression pistons requiring Extreme piston--valve clearance checks/Machining to safely accommodate any longer Duration, higher Lift camshafts or you Easily Bent something extremely Expensive during your "On your Own experimental" cam swap job start up !!
I think that with some better tolerances today and machining skills it helps get a few more hp out of the "factory" motors. The race motors of the time had this 'extra' work and time put into them. But I don't believe for a second that the "street" engines in the factory cars were as under rated as the internet seems to believe. Like the rumors that the L-88 corvette 427 was really a 600 hp engine but ONLY rated at 435 in the car. Maybe 25 hp at most.
The L88 427 was rated at 430 HP to get it under the top normal street 435 HP 427 so unknowledgeable rich kids wouldn't order it... stock L88s dyno at 560 HP @ 6600 RPM with headers... L88s were in the Corvette sales literature... even available with automatic tranny... Aluminum heads L89 or all aluminum ZL-1 427 more like 530 HP as aluminum bleeds off heat/HP faster... but saves weight...
These days it can be difficult locating good useable HEMI parts which have not been altered or damaged so I certainly understand the concern to play it safe on the Dyno. You have a Fun Project and you did a nice job with it but why the 9.6:1 CR? A good OEM spec Street Build should be able to handle 10.0 to 10.5 CR without any trouble. Also, I know you're very pleased with your results and you deserve to be but dyno results from other published builds vary too much, probably due to several things like not getting engine running temps up to their predetermined oil and water temperature windows so that runs can be baselined the same every time. Also, atmospheric pressure, air temperatures and humidity vary sometimes a lot during the course of a day. It is important to get accurate Barometer, Carburetor Air Temperature and Vapor Pressure (Humidity) readings compensated for by calculating your Correction Factor at the end of each run. Your observed Torque and Horsepower curves are then multiplied by this Correction Factor to derive your corrected Torque and Horsepower. Only corrected readings are useful for accurate comparison. Another huge variable, what is the Intake Manifold Temperature at the beginning of each run? Has the Ignition Timing degree of Advance been optimized? Has the Air Fuel Ratio been optimized?
@@moparconnection Apples to oranges. The factory published compression ratios were STATIC. Dynamic is an arbitrary number with a lot of moving parts and is a term some engine builders use to be "trick." Static is the term engineers use.
How is a 9.6 compression the right number you were looking for? The street Hemi had 10.25 compression. As far as horsepower numbers go none of the big three were telling what the true horsepower numbers were as they always picked a lower than peak RPM numbers to give the insurance companies what they wanted power wise.
Not quite.....Most '66--'71 Street hemi engines were Factory built with significantly Larger (173 vrs 170cc advertised specs) cyl heads + significantly Taller block Deck height putting that 10:25 CR spec piston way Down the hole resulting in much Lower ("Bout 9:1) CR....Original owners never Knew unless someone tore down & Measured your engine.....
i think back in the day they did typically underrated the HP , for insurance purposes. It really was weird how just a few HP lower could save you money on insurance. But Ive seen 500 hp on a pretty much stock dinosaur Hemi on cheap pump gas. though i wouldnt recommend doing that daily driving. Lol
Back in the 60's and early 70's those hemi engines were designed to run on pure 100 octane gas with no ethanol or emissions additives. Low 90 / 93 octane was considered regular back then. Not bad considering we have inferior gas nowadays compared to back then.
@@moparconnection Absolutely. Leaded gasoline although bad for the environment, was great for engines without hardened valve seats and catalytic converters. Pure gas is not watered down with a percentage of alcohol or alcohol cosolvents / MTBE etc. Leaded gasoline falls into the "pure" description because it too wasn't watered down.
The octane rating back then was the research octane. Now it is the average of the research and motor octane, and motor is about 10 points lower than research. 100 octane gas in 1970 is equivalent to about 95 octane now, so higher than the 91-93 that you can typically get at the pump today, but not as much higher as you might have thought.
Heartwarming to see evidence of a gas guzzler making awesome HP instead of the usual 14 horses commonly experienced from a stock boat anchor. Those ex. manifolds aren't hurting like might be anticipated so flat against the side. That engine can shred tyres or pull 50 tonnes up hill all day.
If i remember right that's why they called it a 426 hemi . it was the one you wanted in your car on the first date or going shopping on your last ones at 70 🙂
One minor point, if memory serves, the stock engine in 1970 had 10.25:1 compression, and not 9.6:1 as you built it to. So if the compression had been stock, the torque and horsepower would've been even better to a degree,
I'd like to see a comparison of a modern naturally aspirated Modern hemi compared to a gen 2 426 on the same dyno. No gross, net, wheel, or other horsepower b.s..
@@moparconnection If you mean that you couldn't get a hydraulic one made for you, that's a good thing, unless you enter it into a Concours De Elegance, where they would deduct points for not having the correct year engine.
Good video, and fun to see numbers. Why though run not factory compression? If the goal was to show what it could do? I don't know how much you lost but would be some for sure.
Chrysler has ALWAYS understated the numbers on Every(!) engine that left the factory. There's two reasons for this, first is MoPar engineers like to go fast. Second is, no one, ever, can sue them for false advertising on the engine power. Doesn't matter if it was a baby Slant, Minivan V6, Neon 4 or fire breathing Hemi V8, they ALL had more power and torque then the stat sheet claims.
I owned one of the few Hemi Road runners 1970, this car was a brute and was denied at Ramchargers at 495 hp at 6000rpm, I loved it but was sold as kids came and sadly totaled 2 months later
Not likely.....Except on "Happy" dynos, No Factory street hemi made nearly 500 Hp..The very different (Big cam,12.5 CR, Tuned X--Ram intake + Bigger Holley carbs) factory built Race hemi was Typically in the Honest 550--575 Hp range....
From all the Dyno videos and posted Dyno tests posted online not all Hemis are created equal. But everyone made the rate 425 hp(=-) @ 5000 rpm. Yes Chrysler sand bagged. Most make at least close to 450(=-) @ 5500. Hemi like to be tuned to make power. There not a slap together engine like the other big block from another manufacturer. That’s why people build the other big block from brand C. You can slap them together and get more power.
Nick Panaritis of Nick's Garage (www.youtube.com/@NicksGarage/videos) Dyno-tested a BONE-STOCK 426 Hemi set to Factory specs and it pushed out 490+ hp.... th-cam.com/video/QB7Iug0ILAY/w-d-xo.htmlsi=oUT7CXzLf_0m9KqO
I'm really surprised it wasn't more, although I'm not a Mopar fan, the big 3 underrated the horsepower back then to help squeeze thru insurance prices, yes the insurance company's were eating people alive on the high horsepower cars back then too
Back in the early 1970's Hot Rod Magazine said the 426 Hemi was vastly underrated in HP and would make 425 with one spark plug wire pulled. Hot Rod estimated the true HP to be close to 500.
That was based off of a shootout made by Super Stock & Drag Illustrated back in 1969. With some tweaking our Hemi could get closer to 500 but it would certainly sway from stock.
Chrysler was a group that had engineer's who wanted creat vehicles that were the best and executives who wanted to succeed as a buisness and bean counters who only cared about the bottom line and managers stuck in the middle. So they were not the first into racing, it took employees on their own time and money racing for the big wigs to see winning on Sunday sells on Monday for them to green light certain projects. Once they got involved in something they were not going to be shown up, so they dove in head first. What they lacked was the follow thru and appropriate time to allow this projects to get off the ground and flourish. Examples are the Winged B bodies for NASCAR and the TA's and AAR E bodies both made in short runs , Daytonas and Superbirds and 340 6 pak challengers and cudas 1 model year each. Even the Hurst Hemi A bodies were one model year as well but those were not built for the street but the same thought process is still there. Its like see what we can do ...... Next short term project please.... Maybe they had ADD before we knew what that was????
Those "430" hp L-88 427 Chevys actually made 570-580hp with headers. LS-7 454 made 600hp in stock trim with headers. Nothing could run with them back in the late 60s early 70s.
It probably picked up the few extra horsepower due to the better fuel we have today and also the engine dyno Dyno technology is way better than what they had back in the '70s and way more accurate over the analog that we had back then. So you can think of how many engines that we're probably underrated for their time back in the day.
MoPar rated the hemi as 425 HP @ 5000 rpm. What they neglected to say was that the dyno pulls went to 6000 rpm, and at 6000 revs, the engine put out 495 hp. There is a content provider on TH-cam, "Nick's Garage" and he has a weekly show specializing in MoPars. Particularly he works on a ;lot of 440s and hemis, although other engines come into the shop as well. In one of his shows he re-created a stock spec 426 hemi, totally stock except for a .030 overbore. He then ran it on his SuperFlow 902 dyno, and that's what it put out. Sure enough, at 5000 rpm it was 425 hp, but at 6000 the totally stock hemi put out 495 hp.
Ours began to lay over around 5750. You’ll see on the graph. We might’ve been able to duplicate his results with a bit more fuel and timing. Possibly.
@@moparconnection Were you running solid lifters or hydraulic lifters and if you were running solids were they set at .028 intake cold and .032 exhaust cold? Nick tightens the lash up on his until they "sound right"! The factory spec sheet the dealer gave me said .028 intake cold and .032 exhaust cold and .030 intake hot and .030 exhaust hot, didn't say a word about decibels, and they sure did clatter.
Almost up there with my 17' SS Camaro 6spd. rated at 455 net HP. SAE HP at the crank is a little over 500hp factory stock.
@@matrox Funny how many people get different hp figures on the dyno with the 426 hemi, most get 525hp at 6000rpm and power nation got 820hp with a blueprinted 426 hemi, who do you believe? I had a 426 hemi and never found any competition on the street and yeh there were plenty of muscle cars around and many were anything but stock and raced at the local strip and all top fuel dragsters and funny cars run Chrysler Hemis, just a fact of life. All I have to say is having power and knowing how to use it sure helps and spinning isn't winning, always left at 1800 rpm and never power shifted. And let's not forget that the 426 hemi and fords 429 hemi were required to run restrictor plates so the GM cars could keep up and that is another fact of life.
Compression would play a part. This had 9.6:1, Nick's was in the factory range. They say about 5% more power per point of compression. If this had 10.25:1 then that would add about 15 more HP, narrowing the gap a bit. Nicks may have been 10.5:1 but I could be wrong.
The 632hp 505 dual plane single quad Hemi he dynoed was what blew me away.
Nick's garage built one to stock specs too. It made 490tq/490hp.
Nice.
Lol. 😂
He was not running a water pump or an alternator, and his was closer if not at the advertised stock 10.25:1 compression ratio. The water pump and alternator parasitic drag plus the 3/4 point loss in compression will account for the 37 HP difference.
Back in the late ‘80s, we pulled a hemi out of a wrecked Plymouth with a little over a hundred thousand on the odometer. I put it straight on the dyno before pulling it apart to rebuild it. It made 535 horsepower at 6 thousand RPM and held 60 lbs. of oil pressure. I almost didn’t want to pull it apart but it had a leaky head gasket and a broken ring so it smoked like crazy. .30 over on the bore, a nice cam, fresh bearings, and a little carb jetting, it made just under 700 hp. Still running today, never opened since building it. Good motor.
Heck yeah!
Impressive story !! ......Without any engine build/tune data, inferences to 6 digit odometer #'s & smoke "hurt" runnin condition, seems youall found the rare 20yr old, wore out 1 cylinder down "unicorn" hemi still producing new Factory built super stock race "Package" engine power numbers Especially after the relatively simple 030 over & bearings fresh-up, "nice cam" & carb tweaks & wakin up crankin over the top dyno #'s requiring an impressive Torque curve.....
@@tomstrum6259 the 426 was so underrated by the factory, it’s almost shameful. Insurance companies were starting to crack down on covering muscle cars was the reasons given, but I don’t know. As for the car it came out of, I watched the odometer roll over on a road trip before it was wrecked because it belonged to my cousin who bought it new. A set of headers, a jet change in the factory carbs, and timing right off the factory floor bumped the hp numbers by almost 3 figures alone. The Chevy LS6 made similar numbers with the same minor mods, not a fan of Chevy, but I built one for my dad to replace the wore out 396 in his Chevelle that he bought when he got home from Vietnam. I’m not claiming to be some expert or guru, but I have been building drag engines since 1984, mostly for myself and close friends.
To each their own "memories" I spose.....Chrysler advertised the production Street hemi power & torque ratings very accurately & honestly....425 actual on average, some better some less.....Whatever winds yo crank man.....
@@tomstrum6259 Is that why power nation blueprinter a stock 426 hemi and got 820 hp with it on a dyno? Guess you should contact those who did the testing and tell them they had a bad dyno, huh?
Beautiful Cuda. I'd rather have a tribute car than a museum piece you're terrified to drive and have fun with. Drive it like you stole it!
Amen!
I have a numbers matching beautiful AAR Cuda and I simply cannot drive it. It is really a shame. These cars are worth way too much to drive anymore. I like to call it a 3600 pound paperweight. I will be selling it soon and just driving around my 1971 340 Duster. It isn’t worth that much.
Thanks for your approach to this Hemi build. The HP of these engines are all over the place. This is a good approach at what might have been delivered to the public in the 70’s. The Hemi is the most legendary engine offered in the 60’s and 70’ s and that is without a doubt. You either wanted a Hemi or you wanted to beat a Hemi. It was the litmus test on the street. Wether it lived up to the hype or not is not the answer. As legends go it got bigger and bigger in street lore. And as the top engine used in top fuel it also backed up the hype. Yes an LS6 454 is legendary too. As is the 427 Ford. Even small blocks have status. But the Hemi sits on top because of the hype. I have never owned a 2nd Gen. Hemi but I drove one one time in 79. A 66 Hemi Charger automatic. And I only got into it a little bit. But the torque was without question evident to me. If you wanted a Hemi to rule your streets, it took more money and wrenching. But it was an awesome starting package. Headers and a high lift cam would give back startlingly results. But tuning the distributor and carbs was a must after such modifications. The Hemi was a detuned race engine. And you had to return it back to what it needed to be with the right parts. You could go full bore and add 12:1 pistons and oil mods too. It was just what you could afford to do. Same with the other big blocks available at the time. It was definitely a different world in those days. And I miss them. Simpler times. Thanks for the video.
No this was meant to be a tribute to the car as it wouldve been in the showroom. I’m personally building a 572 Hemi that’ll be quite rowdy.
@@moparconnection I know. That is why I said your approach was as it would have been delivered in the 70’s stock factory car. Or my meaning was such. I bet that 572 is a beast. Now that is legendary.
I would argue it having the top "legendary status". I would say the ford cammer has more legendary status. What people's actual opinion is of the engine might vary. But as far as legendary? My vote would be the cammer. Becouse who dous anybody know that actually has or had a cammer?? In a rare moment one might see a hemi. But most never see a cammer in a liftime.
Yes I’m a Ford guy. I love the camera however it was never put in our car. Chrysler somehow offered from 66 to 71 like you say it was incredible time in history. I am 61 years old. I miss those days cruising Whittier Boulevard I graduated 81 back then you could buy a street hemi for around 04 to $5000 believe it or not. I remember gas being way under a dollar a gallon.😢
@stevo196two9 ur right, there is no Vin code that would indicate a factory cammer car. It was made available though as a "high rev, race ready, replacment engine" for your new Ford car. A over the counter ford replacment part.
Thx for truthful informative video...Your Dyno performance numbers seem just about right..With 1000 miles, my factory pure stock '70 hemi cuda Automatic click off 13.1's @ 107 all summer day long with full gas tank @ 4000 lbs.....Carbs never Touched, 4.10 Dana, 35° timing ....
Nice!
With stock tires?
@@kirkthejerkthe1stI seriously doubt that lol
@@midnight347 truly, why would you want a stock hemi?
@@oscaroscar5336 When they were new they were stock..they ran high 11's once carbs set and better tires! Tracks and tires were not sticky like today!
Correct me if I’m wrong, but it’s my understanding that the 70-71 Hemis were hydraulic cammed. I love to see the difference of the 70s Hemi vs early models with solid lifters.
66-69 were solid/mechanical. 70-71 were hydraulic.
Engine Masters tested the 426 Hemi vs a 440 and it turned out the hemi was great for….high sustained rpm but the 440 made killer torque for drag racing
Makes perfect sense
The difference in tq comes from the cubic inches not the top end. If a hemi had as many cubes it would have made just as much tq and way more hp.
@@DavidPhillips-rs5dq yeah and if a 318 was 800 cubes... it would make more power. BUt guess what.... it isn't Don't blame the OP because mopar never put any cubes behind the hemi heads.
@@DavidPhillips-rs5dqNo that’s not the reason. The Hemi heads are top end flow and suffer a bit down low. It could be a 440 Hemi and still make less torque than a 440
@@wyo_garage20 wrong
Awesome video. 👍 My Mopar is my 1968 Barracuda fastback powered by a 400 based 512 stroker featuring Trick Flow 240 heads and a hydraulic roller cam with 254 duration @.050 with 618 lift, backed by an A833 4 speed manual. 👍
Very cool!
I had a 68 b5 blue fastback barracuda. 340 four speed car. Got rear-ended by an excursion
People dont realize the StreetHemis were detuned race motors, which dont work real well on the street in daily use. A well tuned stock 440/6 will out run a Hemi half the time. We ran a 64 RaceHemi with aluminum heads and a Hilborn injector system in a steel 37 Willys coupe and it put out way more than 650hp on a basically stock motor (no wild cam or exotic stuff other than the injector and magneto)
Oh yeah, worse than that. Street Hemis weighed 812lbs, had lazy hydraulic camshafts and sloppy, misaligned valvetrain. Nothing about them were high performance.
The key to longevity of a race motor on the street is to drive it like your at the track, even to the grocery store😂
Joking aside, I do have just a bit of Machine shop experience under my belt, growing up in Flint, Michigan at Precision auto & Machine shop. I've never seen a pachyderm on the dyno that put out less than 435 h/p, most are up there around 450-480, Mopar really built a beast when they built that HEMI. Thanks for sharing this with all of us, I'm sure everyone else enjoyed it as much if not more than I did.
👍🏻
@@chadhaire1711put down the crack pipe Nancy 10% parasitic loss 450 gross is 405 net.
They all heavily underrated their engines. I have a theory that since they sold the cars all over the US. They needed to make sure even in say Denver the engines would put out their advertised HP.
Today our advertising laws are extremely lax. You can tell someone your polonium tea cures cancer and as long as no "reasonable person" would fall for your advertising. Well you can't be sued for false advertising. But our advertising laws weren't always like that.
It was for insurance purposes, less than 1 hp per CI, Ford 428 claimed 427hp Chevy 427 claimed 426hp.
@@chadhaire1711 it's 10% parasitic loss... 450 gross is 405 net.
A friend of mine had a '70 GTX 426, convertible, auto on the column. If it was only 425 hp, it was a STRONG 425! He never got beat by anyone locally on the street. It was a beast. I don't know why you didn't do a pull at 6,000. The '70 GTX shifted at 6200 if just left in "D" to do it's own thing.
Interesting.
I have a 426 in my '68 charger ( not original )
Its a late '66 casting.
The engine was built by Al Lee, of Lee brothers ( ' 68 hemi SS barracuda fame )
I talked to him after installing the engine and he told me he had punched it out 60 thousand and installed the correct factory mechanical cam.
Other than electronic ignition and a gorgeous 3" TTI exhaust, its totally stock right down to the Carter carbs.
Al told me, from his experience, it should be just a little over 500 at the flywheel.
This summer i plan on taking her down the 1/4 to see.
Awesome! That sounds like a lot of fun!
I remember when Jim Drain from FL went out to see the 426 he had Dick Landy build, it made 525 HP and Jim was mad about it as it was going in his 1967 GTX Hemi 4 speed that was a pretty much an NOS car and the engine was supposed to be a stock rebuild. Dick just told Jim to calm down and when the Hemi was properly blueprinted, it would make these kind of numbers.
Dick knew what was up.
@@moparconnectionhe was Dandy
My wife has a real 71 Cuda, 340 4 speed, Bahama yellow. Needs a full resto, which is on my list, but for now it's protected
Whoowee! Gotta get on that project!
You guys aren't getting a divorce anytime soon are ya'?😊
Nice to see some honest work giving honest numbers.
Appreciated!
@@chadhaire1711 Wouldn't that be rear wheel hp? That engine wasn't installed.
Thanks! Certainly no other engines could match the street hemi in 1966 when it came out and they would make more power in the upper rpm range than anything else.
Not the street ones, but with a little bit of love they screamed!
396 425hp and 7200 with ease in stock form
So it couldn't come within 50 hp of a hemi? That's nice
In 1967 Chevy responded with the "430 HP" L88 427" engine in the sales literature... that was actually 560 HP at 6600 RPMs...
The boss 429 was a monster. They were detuned for street cars and could make crazy power with minor tweaks.
I liked the honesty of this pull. From what a stock Hemi was doing in the day. About 450-460 is quite good. Many dynos are kind of “ happy “ and they have caveats. This is straight up.
It was pretty darn close!
In 1970 Hemis came with a hydraulic cam I believe, so no E body solid lifter cams.
I’d love to see documentation for that because we couldn’t find it elsewhere.
This doesn't sound right, but according to my vintage Motors Manual (early model edition 1968-1974), only the 1971 426 came with hydraulic lifters. All other 426's were solid lifters clearanced at .028 intake and .032 exhaust (cold). The hydraulic cammed cars had adjustable rockers and a spec. for that.
The 70-71 Hemi’s all had hydraulic cams, the specs were the same as the 68-69 series 2 cam, just hydraulic, and they still retained the adjustable rockers, but shorter push rods. Just look in any 70-71 service manual for documentation.
Just as I originally stated. My Motors Manual must be wrong!
@@moparconnection He's correct, hydraulic lifters for Hemis starting in 1970. It's called out in the '1970 Challenger Lineup' dealer binder, and again in the 1970 Plymouth Rapid Transit System advertisement, page 15. I'm sure it is also called out in the factory service manuals, but I don't have a '70 on hand. No solid lifter E-bodies.
That driver side front exhaust port looks like the manifold is strangling it compared to the others.
It’s what came from the factory
I understand, It's just a horrible design that was clearly the victim of packaging constraints.
Yep, switching from stock Hemi manifolds to headers was worth .3 all by itself for me at Muncie Dragway.
It had to be that way to clear the steering box.
Im sure Mopar didnt like it either.
Back in the day, insurance company's would not insure a car that had a greater than 1:1 hp/cid ratio. Hence 426 cid, 425 hp
Bingo
Smooth job, guys! Mopar queen and the king of engines💪 Perfect!👌
We agree!
Thanks for sharing great video
Thanks for watching!
Hey thanks for the response on compression. I love watching the videos, have a great day. Thats crazy how the actual numbers would that off.
Yeah it’s super disappointing but given how expensive and frankly, difficult the Hemis were to machine, racers and builders found all sorts of inconsistencies.
I traded a guy a boat for a '70 'Cuda w/ a 383 and one of the factory pistol-grip shifters, that I later found a Hemi for, along w/ one of the cross-ram intake systems Mopar developed specifically for these engines and high performance applications. What a screamer! With two Carter 850 CFM carbs it ran just over 10 second 1/4 miles. My favorite exercise was cruising at 3K-4K RPMs in second gear just to hear that engine sing. Back when I thought everything was replaceable, because I sold that jewel - its replaceable, right? smh
Holy cow! That's amazing!
Thanks for that awesome demonstration of the beloved hemi!🇺🇸
Glad you liked it!
I have a 1969 Car Craft magazine issue in which they drag race test a 69 Roadrunner 440 6 pack automatic. They fiddled around with it and got some decent times out of it with slicks. As evening approached they realized the exhaust manifolds were glowing red hot after each pass and obviously a set of headers were needed. I've seen a true survivor Hemi Roadrunner that was absolutely bone stock but most people that bought a Hemi car for performance NEVER left it stock. A set of correctly made headers that match the stock cam and a correctly recurved factor distributor and the factory carbs rejeted by someone who knows what they are doing is worth 65 horsepower minimum so who gives a flip what the engine would do off the showroom floor ??
Precisely
Agree
Had a 1967 Satellite with the 426 Hemi 4 speed dana 60 with 3.54 gears with a track lock. I believe the compression was 10.25:1 with a slightly smaller cam then the 68&69 Hemi's. First thing I had to do was adjust the valve lash, .028 intake and .032 exhaust cold, oh my did those lifters clatter, everyone who got in the car told me there was something wrong with the engine. I know for a fact that many dealers would set them at zero lash because people would not buy them for that reason. I made two changes to the engine, one; a set of chrome moly pushrods and two; added a braided copper wire between the stationary plate and the breaker plate to eliminate ignition breakup from 5500rpm to 7000rpm. And for whatever it is worth yes it would turn 7000rpm in every gear and no you didn't hold it there in any gear so as not to grenade it and you didn't power shift it into any gear unless you wanted to do a donut. It was on H70/14 Dunlap bias ply tires so there wasn't a lot of rubber on the road. Don't understand why people complain about the Hemi being a dog on the street unless they just didn't know how to drive it. And I have talked to a few former Hemi owners and no they didn't. And hey even Nick from Nick's garage tells me he reduces the valve lash until it sounds right to him!!!!!! Gee I wonder if that's why they had a reputation for valve train wear, DUH!
That’s an awesome story! Man, that sounded like an awesome car.
Yea it was and I still miss it. I have a 66 Satellite and a ton of 440's, 400's, 383's, 360's, 340's,318's, but no Hemi. Now if I could just be lucky enough to hit the lottery! I am guessing you know enough to run a remote oil filter and pipe one return into the passenger's side at the rear of the block where the sending unit goes, this will prevent oil starvation on 6,7&8 rod bearings at high rpm and you know to keep your engine loaded, pulling, when winding it so as not to blow it. No better way to blow an engine than to wind an engine with no load on it, another reason why I never power shifted.@@moparconnection
That's odd. My 70 340 6bbl, had a similar distributor, Prestolite dual point, and it came oem with a braided copper ground wire.
Don't know what to tell you, but the distributor in my 67 did not have one until I installed one, maybe someone at the factory figured out the same thing I did and yours was a 70 and mine was a 67 and as we all know the factories were always making changes. You're making a big assumption that because your 1970 distributor had one that my 1967 distributor had one.@@budlanctot3060
@@stephenwest798The Hemi will also have piston slap noise when cold too. Did you do the lash the same way us HyperPak Slant blokes do? - While It's Running 😊 Gets perfect lash at operational temperatures, solid cam and lifters (like the 273's had in the 60's) on the stock Slant always sounds like a sewing machine running somewhere under the hood. But once it's right, throttle response is crisp, and the emissions go way down, same with fuel usage out on the freeway. The valve train with correct lash and replacing the stock phenolic cam gear and morse chain with a roller chain and gears on the Slants and the V8's, the valve timing stays perfect, the ignition timing stays perfect, the wear goes away to the point you can run the Lean Burn computer and have it be reliable. Check the lash every couple of filter changes, these things just keep going.
My buddy who is working on my 70 442 is a huge mopar guy. He has some really cool cars trucks ect.. I think its a replica but 1 truck he has is The Little Red Wagon he takes it to Cordova for some show every year
Very cool!
I can confirm this is an early factory HEMI solid lifter cam (or repro) as I measured the lobe lift in my lathe and it was right on spec.
Thank you!
When you say early, does that mean the mild series 1 solid cam used in 66-67, or the bit wilder series 2 solid cam used in 68-69.
Most likely 68-69 based on specs. I meant early as its a solid cam and not the Hyd correct for 1970. @@jamesblair9614
How about a 2 or 3 part series on optimizing a Six Pack setup?
Not on this one, no.
I remember the good old days!🤗
Great video there Kevin love to see them all cars back on the road in excellent shape great horsepower and torque love the video
Glad you enjoyed it!
Great numbers on the dyno , even with a fairly low compression ratio. Street Hemis were no slouch.
Most were dogs due to their weight (812lbs) and inconsistent machining.
You mentioned this was rebuilt from a bear body. That would have been very difficult, because I rebuilt one from a hippopotamus body and that thing was a monster. So, hats off to you.
“Bare” is a very different word than “bear.”
@@moparconnection It was an attempt at a little humor on my part. Yeah, it wasn't that funny.
To be fair, we get a lot of comments from folks who otherwise wouldn't know the difference.
Nobody knows how to get hp out of a hemi than Nick! he's the best!
He’s brilliant
Uh, I would not discount Ray Barton!
One of the guys from Holman Moody said that the 427 Fords that were sent to their shop to be prepped for NASCAR came to them at about 510 hp. So they pretty much use the parts. The Ford gave them and just blueprinted of the engine. The street version that was in the cobra put out about the same as the hemi. 425 hp. I suspect the Chevy was about the same because we know the “special“ engines were producing the same 500 hp as the Ford race engine was. For the GT40 and other endurance racing they tuned all of those engines a little bit.
What is the story on the TRACO remote oil filter mount, bolted to the frame under the oil filter? Looks like it has a sensor connected to it?
Great question! I actually don’t know so I’ll have to ask.
Cool video,never seen a hemi before 84. But had worn out a few 440s,360s.
👍🏻
A couple things.... wasn't the street hemi a hydraulic lifter engine?
Also, blue printed engine should make more power than an off-the-line one.
Where the hemi really excelles.... great lower rpm lift and stout bottom end - make for a really nice and reliable forced induction engine.
Yes all street Hemis were hydraulic flat tappets.
NO !! ....All 1966 (First yr hemi option) thru 1969 Street hemis came with Solid lifter flat tappet cam with only 1 slight cam upgrade during that 3 yr span....Hydraulic Only cam in '70--71 yrs....
I seem to recall the stock compression ratio on the OEM spec 426 HEMI was 10.25 to 1. I think yours is a bit low. That's a really nice engine, and represents the legend of the street HEMI quite well. Sounds healthy.
That was advertised yes, but records show that many of these came out of the factory with far less compression. Quality control was not the best.
So, 438 CID, but compression a full point lower than the Street Hemi. Those deviations may offset and get you close, but I'd still like to see what real factory-spec hemis made. I suspect that will keep getting harder to find as years go by.
Not quite. While Chrysler advertised 10.25:1 many engine builders found their street Hemis had far below that compression ratio. The compression height of our pistons, rod length and crank all remained identical to stock. The block wasn’t decked and we compensated for the decked heads with a thicker gasket. It came out to 9.6:1.
450/480 sounds more like reality. Too many guys saying they made sooo much more like 100,
lol. That torque curve kicks butt for any st car. So many focus on a hp number but totally ignore the tq which is where it makes the beans.
Torque is where it’s at!
Back in those days there was high octane fuel at every gas station....You could run 12 to 1 motors with no issues...
That wasn’t because of octane but LEAD content.
@@moparconnection It was always rated in octane because of the higher tetraethyl lead content...Back then 110 was normal....And aviation fuel was 125/145 octane...
I owned a 440 6 pack cuda with only headers and a 4:10 Dana - 4 speed . Car was consistently 11.8 to 12.0 in the 1/4.
Not too many Hemis were tuned properly to beat it "
That's a heck of a combo. Must've been a helluva ride!
Man I love engine rebuilds! Pontiac was the same way with sand bagging the power!
Most all were
I loved building my uncles 68 gen 2 barracuda. The hemi 426 we went mid way on build ( first start up vid on my TH-cam channel) Dean @ big AL'S toy box and AL the owner assembled and dyno'd the 66 block and performance parts . Pulled 650 hp / 750ftlb on 93 octane
Very nice. You guys did a great job!
@moparconnection ty very much
I've heard many made around 450hp at the crank. Some made close to 500 HP at the crank.
My cousin saw one with headers and slight turning made close to 600 HP and went 10.9 in the quarter mile ( with slicks)
Race Hemis certainly did, and a heavily modified street Hemi could make some serious power but the as-is street Hemi was stout but limited.
We are talkin Chrysler factory Stock production line built & delivered cars ?? ....Everyone gots the passed down "Cuz" car "story" I 'spose.....'Cept in yo dreams, ...No Chrysler production factory cammed '60's--'70's big block (Street hemi included) lead sled lame cammed & hardly any compression muscle car got near Slick tires 11's or 10's 1/4mi time slips....Whatcha smokin ??
I noticed you stated compression as 9.6 to 1. Factory specs are 10.25 to 1 street version. Race version 12.5 to 1.
We didn’t do a clear job of stating that we were measuring dynamic compression not static. The 10.25:1 ratio was static.
Should've sleeved it so it really was the factory displacement and restored the cylinder strength.
It had crossed our mind but would’ve doubled the cost of the machining.
Would have been far better off pulling out useless mass with modern pistons and rods, and not having to further sodomize the crankshaft welding mass back into it. Could have really been money ahead going to 2.200 BBC rods on the crank throws. But I get that it's fun to see what the old junk would do "back when" and it's a cool car, with a resto build engine.
“Sodomize the crankshaft” - bro, calm down.
@@moparconnection 🤣🤣
I thought your team did a great representation of a stock 426. QUESTION: Im curious of what the gap was from the top on the piston and the block deck ?
The factory pistons were .022 "in the hole."
The 1970-71 Street Hemi had a hydraulic cam with same timing specs as the 69 solid cam...so they say. You could not find a correct hydraulic cam? My brother still has his 1970 Hemicuda he ordered new. I have the original factory hyd. cam which had 10,000 miles on it. I set it up in my lathe and like you checked out the numbers. I got 228 degrees duration at .050 and a gross of 284. Lobe lifts at .309 to .311 I made a dummy lifter of the correct diameter of a stock Hemi lifter and dial indicator off of that.
Find a major camshaft manufacturer that reproduces the original cams. We had to have COMP grind one close to stock.
Back in the day the 426 was no joke especially when you had high performance 3 duce 4 speed the I was around in 75 had never been rebuilt and turned 6000 rpm with no complaints.
No such thing as a triple deuce Hemi from the factory. Only dual quads.
one use to have i forgot was 70 or 71 Hemi Cuda back in 1971 and he used to race it a lot in Kuwait later it went to junkyard.
Oh my gosh!
A good stock Hemi with a sharp tune is in the 480-490hp range. Around 500tq.
A lot of these came out of the factory undertuned!
Look at that exhaust manifold port on #1. It's almost like having a block off plate there. That's part of the power problem.
It's factory. What are ya gonna do? LOL
You can pull a spark plug wire off and make a 425 hp pull with a 426.
That’s the rumor but that was with a ‘66.
I remember a magazine article back in the day where the author after driving a stock 426 Hemi car opined that he thought it was closer to 500 HP than it was to 425 HP.
We show it’s more powerful. Dyno results are real
The hi po engines back then always put out more power. They lowered the numbers for insurance purposes. Great build.
Some did, yes. Others manipulated how HP was calculated/
That's true
Lol, no.
Lower numbers also mean that one customer that hates everybody couldn't sue over finding out it had less power or torque then claimed.
Americans were far less litigious pansies back then.
Everyone know that most of these engines had more power than advertised.
BUT you have fitted it ro a tent car,, they flex badly. Then fitted with the tyres that killed hundreds,, Badday Polyglass. So you have a 140mph car with a 70mph chassis on 20mph tyres.
👍🏻
I never knew that the #1 cylinder exhaust manifold was so restricted.
Factory stock wasn't very forgiving to these engines.
They had no choice.
It had to clear the steering box.
Basically you lowered the compression with those super thick gaskets by at least .5 leaving you at 9.75: 1 or lower and reducing factory power output by at least 25hp.
You DO know the difference between dynamic and static compression, right? We're exactly as stock.
@@moparconnection Of course. DCR is always lower than SCR and DCR is fixed unless you installed VCT on that hemi, Right? The fact is that you lowered the SCR by using monstrously thick head gaskets thus losing over 25hp.
What was your timing?
As I recall we were at 20 initial and 38 all in.
Always loved these old engines. I will say this, though: "From the factory", it wouldn't make this same power level. You have the additional bore, of course which couldn't be helped....but it does add power. 8-10hp, easily. In the big picture, that isn't a lot but in this case when we're talking "what did it do off the showroom floor?", it matters.
Then the heads...no way they don't have a better valve job, since they were on a drag motor, right? That helps. And I'm sure it's balanced.
So while it's about as close are you're going to get these days, I'd say an actual "out of the box" Hemi would be down a bit from where this one is.
Still gets us in the ballpark, though.
👍🏻
That will put a smile on your face
😁
You can see clearly from the chart that after 5500 rpm, the power dropped off. That means that in this configuration, this engine made 452. 7 hp tops. It is only turning a water pump and an alternator with an open headers exhaust, which means that this is basically gross horsepower. Modern Ford Mustang 5.0 liter/302 cubic inch DOHC 32 valve engines make 480 hp at the crank but that is NET horsepower.
These old engines are fascinating, but they aren't what people think they are; Modern Hemi's would use one of these "elephants" as a breakfast food....
👍🏻
EXACTLY... NONE of the old stuff trapped MPH numbers to back up the horsepower "claims"...
Another thing the big 3 did, was to leave off things like alternator, water pump and mufflers or anything that would sap horsepower. We have to mention also, that the horsepower rating system went from gross horsepower to S.A.E. net horsepower in 1972. This meant a certain standard was adhered to, like mufflers, water pump and the room at 70° Fahrenheit. The year prior (1971) saw the first round of emissions phased in. While none of this affected a 1970 engine, we no longer live in the year 1970 and horsepower today is measured in S.A.E. net. I find it amusing that gross horsepower is still used in some areas, like rating lawn mowers or farm equipment.
They ran water pumps in the dyno
I SEEMED TO HEAR A VERY LOUD TICKING, VALVES ? AFTER THE PULL. DID I HEAR CORRECTLY?
Admittedly the audio equipment I used wasn’t very good. It picked up a lot of noise that was distorted. The Hemi ran great.
Probably more like 465-475 with 10.25 compression like factory. Great job.
No the compression is still under 10:1.
Why didn't you put shelves in the cylinder bores to match factory spec?
I've never heard of "shelves" in cylinder bores. Do you mean chamfers?
@@moparconnection
I think he means sleeves.
Mopar Connection Magazine....In fact, the only way to build a ''numbers matching motor'' for this car was to rebuild the 318 original motor...That is the only way...any other motor won't match...unless you punch new numbers on the replacement motor that you stick in it...
At the most anal of definitions, yes you are correct. We mean replicating a DATE-correct build.
@@moparconnectionwould an unstamped warranty engine,with correct casting date count as Number matching?
What an absolute legend the Hemi is. But no, not just a legend; the beast really delivered.
Absolutely. Not a legend but raw reality. Tons of power in that block of iron.
👆🏻
Nice video Kevin.
Would have been nice to seen some of the machine work and parts as well as the processes.
Should be a great engine.
Have a great day.
That’s why we linked the three dozen articles we wrote on it.
Remember that is a street Hemi. I'm guessing the race Hemi had more like 600hp
Absolutely- if not more!
The std Available factory options should've Included something similar to the "Max Wedge" X-ram intake Holleys & properly Cam'd & High domed factory Race version....550hp flywheel Easy.... Would've been a Total game changer Max perf street car....but they Didn't.....
There were plenty of options through Direct Connection to hop up the engine once it left the dealership.
There was no "Direct Connection" dealer Participating support during '66 thru '71 available until 1974 ....No Factory/dealer help at all for Original Street owners & Typical Chrysler dealers had No knowledge or showroom Brochures on the very rare limited Production, race Only drag package car componets so You were on your Own in middle of "Nowhere USA" & No dealer support.....Unlike the extreme limited production, Factory S/S race car package Hemi with Deep plunge cut valve Relief pistons, All street hemi engines came with Extremely tight valve relief low compression pistons requiring Extreme piston--valve clearance checks/Machining to safely accommodate any longer Duration, higher Lift camshafts or you Easily Bent something extremely Expensive during your "On your Own experimental" cam swap job start up !!
I think that with some better tolerances today and machining skills it helps get a few more hp out of the "factory" motors. The race motors of the time had this 'extra' work and time put into them. But I don't believe for a second that the "street" engines in the factory cars were as under rated as the internet seems to believe. Like the rumors that the L-88 corvette 427 was really a 600 hp engine but ONLY rated at 435 in the car. Maybe 25 hp at most.
The race Hemis were absolutely a different animal than the heavy, slow revving street Hemis.
The L88 427 was rated at 430 HP to get it under the top normal street 435 HP 427 so unknowledgeable rich kids wouldn't order it... stock L88s dyno at 560 HP @ 6600 RPM with headers... L88s were in the Corvette sales literature... even available with automatic tranny...
Aluminum heads L89 or all aluminum ZL-1 427 more like 530 HP as aluminum bleeds off heat/HP faster... but saves weight...
These days it can be difficult locating good useable HEMI parts which have not been altered or damaged so I certainly understand the concern to play it safe on the Dyno. You have a Fun Project and you did a nice job with it but why the 9.6:1 CR? A good OEM spec Street Build should be able to handle 10.0 to 10.5 CR without any trouble. Also, I know you're very pleased with your results and you deserve to be but dyno results from other published builds vary too much, probably due to several things like not getting engine running temps up to their predetermined oil and water temperature windows so that runs can be baselined the same every time. Also, atmospheric pressure, air temperatures and humidity vary sometimes a lot during the course of a day. It is important to get accurate Barometer, Carburetor Air Temperature and Vapor Pressure (Humidity) readings compensated for by calculating your Correction Factor at the end of each run. Your observed Torque and Horsepower curves are then multiplied by this Correction Factor to derive your corrected Torque and Horsepower. Only corrected readings are useful for accurate comparison. Another huge variable, what is the Intake Manifold Temperature at the beginning of each run? Has the Ignition Timing degree of Advance been optimized? Has the Air Fuel Ratio been optimized?
Besides we’re measuring DYNAMIC compression (9.6:1) not static 10.5:1.
@@moparconnection Apples to oranges. The factory published compression ratios were STATIC. Dynamic is an arbitrary number with a lot of moving parts and is a term some engine builders use to be "trick." Static is the term engineers use.
How is a 9.6 compression the right number you were looking for? The street Hemi had 10.25 compression. As far as horsepower numbers go none of the big three were telling what the true horsepower numbers were as they always picked a lower than peak RPM numbers to give the insurance companies what they wanted power wise.
We’ve answered this thoroughly in other comments.
Not quite.....Most '66--'71 Street hemi engines were Factory built with significantly Larger (173 vrs 170cc advertised specs) cyl heads + significantly Taller block Deck height putting that 10:25 CR spec piston way Down the hole resulting in much Lower ("Bout 9:1) CR....Original owners never Knew unless someone tore down & Measured your engine.....
i think back in the day they did typically underrated the HP , for insurance purposes. It really was weird how just a few HP lower could save you money on insurance. But Ive seen 500 hp on a pretty much stock dinosaur Hemi on cheap pump gas. though i wouldnt recommend doing that daily driving. Lol
This was an almost perfect stock example and made a little over 450.
Back in the 60's and early 70's those hemi engines were designed to run on pure 100 octane gas with no ethanol or emissions additives. Low 90 / 93 octane was considered regular back then. Not bad considering we have inferior gas nowadays compared to back then.
Leaded gas made the biggest difference
@@moparconnection Absolutely. Leaded gasoline although bad for the environment, was great for engines without hardened valve seats and catalytic converters. Pure gas is not watered down with a percentage of alcohol or alcohol cosolvents / MTBE etc. Leaded gasoline falls into the "pure" description because it too wasn't watered down.
The octane rating back then was the research octane. Now it is the average of the research and motor octane, and motor is about 10 points lower than research. 100 octane gas in 1970 is equivalent to about 95 octane now, so higher than the 91-93 that you can typically get at the pump today, but not as much higher as you might have thought.
Ethanol adds hp generally as it is carrying extra oxygen into the mixture... sort of like adding a small shot of nitrous
Heartwarming to see evidence of a gas guzzler making awesome HP instead of the usual 14 horses commonly experienced from a stock boat anchor. Those ex. manifolds aren't hurting like might be anticipated so flat against the side. That engine can shred tyres or pull 50 tonnes up hill all day.
Heck yeah!
If i remember right that's why they called it a 426 hemi . it was the one you wanted in your car on the first date or going shopping on your last ones at 70 🙂
👌
I did in summer '70.....Kinda cramped at Drive-ins but we managed !!!
Why not sleeve it to stock bore?
That's fine, just box it up and I'll be there about 9am tomorrow to load it up. lol.
😆
Elephant Power!
Yessir!
One minor point, if memory serves, the stock engine in 1970 had 10.25:1 compression, and not 9.6:1 as you built it to.
So if the compression had been stock, the torque and horsepower would've been even better to a degree,
You DO know the difference between static and dynamic compression, right? The compression is 100% correct.
I'd like to see a comparison of a modern naturally aspirated
Modern hemi compared to a gen 2 426 on the same dyno.
No gross, net, wheel, or other horsepower b.s..
It would be interesting for sure
My two favorite engine sounds: a radial aircraft engine and V8 running wide open. They don’t run they roar!
This Hemi is a bit of a pussycat
@@moparconnection yeah but it still has that sound.
Super cool video
Thanks!
Good thing you used an earlier solid lifter version. The 70 - 71 used hydraulics and wasn't quite the same.
We couldn’t get one made for us
@@moparconnection If you mean that you couldn't get a hydraulic one made for you, that's a good thing, unless you enter it into a Concours De Elegance, where they would deduct points for not having the correct year engine.
Good video, and fun to see numbers. Why though run not factory compression? If the goal was to show what it could do? I don't know how much you lost but would be some for sure.
We did. Factory crank, rods and pistons with the identical compression height. The factory was famously inconsistent and this was one example.
Chrysler has ALWAYS understated the numbers on Every(!) engine that left the factory. There's two reasons for this, first is MoPar engineers like to go fast. Second is, no one, ever, can sue them for false advertising on the engine power.
Doesn't matter if it was a baby Slant, Minivan V6, Neon 4 or fire breathing Hemi V8, they ALL had more power and torque then the stat sheet claims.
Hmm... it wasn't due to people being litigious in the 1960s and 70s but insurance companies and the federal government.
@@moparconnection "No one",... includes Da Gubermint,... ;)
( Smiles in Slant Six HyperPak VC Valiant )
I owned one of the few Hemi Road runners 1970, this car was a brute and was denied at Ramchargers at 495 hp at 6000rpm, I loved it but was sold as kids came and sadly totaled 2 months later
😳
Not likely.....Except on "Happy" dynos, No Factory street hemi made nearly 500 Hp..The very different (Big cam,12.5 CR, Tuned X--Ram intake + Bigger Holley carbs) factory built Race hemi was Typically in the Honest 550--575 Hp range....
From all the Dyno videos and posted Dyno tests posted online not all Hemis are created equal. But everyone made the rate 425 hp(=-) @ 5000 rpm. Yes Chrysler sand bagged. Most make at least close to 450(=-) @ 5500. Hemi like to be tuned to make power. There not a slap together engine like the other big block from another manufacturer. That’s why people build the other big block from brand C. You can slap them together and get more power.
Not necessarily more power but certainly CHEAPER.
Nick Panaritis of Nick's Garage (www.youtube.com/@NicksGarage/videos) Dyno-tested a BONE-STOCK 426 Hemi set to Factory specs and it pushed out 490+ hp....
th-cam.com/video/QB7Iug0ILAY/w-d-xo.htmlsi=oUT7CXzLf_0m9KqO
Nice!
I'm really surprised it wasn't more, although I'm not a Mopar fan, the big 3 underrated the horsepower back then to help squeeze thru insurance prices, yes the insurance company's were eating people alive on the high horsepower cars back then too
We all believe this claim that they all “sand bagged” but it isn’t necessarily true
Back in the early 1970's Hot Rod Magazine said the 426 Hemi was vastly underrated in HP and would make 425 with one spark plug wire pulled. Hot Rod estimated the true HP to be close to 500.
That was based off of a shootout made by Super Stock & Drag Illustrated back in 1969. With some tweaking our Hemi could get closer to 500 but it would certainly sway from stock.
Don't care what carb & timing tune tweaks done to bone factory Stock street hemi, takes a real "Happy" dyno to get >450hp street hemi built #'s......
Chrysler was a group that had engineer's who wanted creat vehicles that were the best and executives who wanted to succeed as a buisness and bean counters who only cared about the bottom line and managers stuck in the middle. So they were not the first into racing, it took employees on their own time and money racing for the big wigs to see winning on Sunday sells on Monday for them to green light certain projects.
Once they got involved in something they were not going to be shown up, so they dove in head first. What they lacked was the follow thru and appropriate time to allow this projects to get off the ground and flourish. Examples are the Winged B bodies for NASCAR and the TA's and AAR E bodies both made in short runs , Daytonas and Superbirds and 340 6 pak challengers and cudas 1 model year each. Even the Hurst Hemi A bodies were one model year as well but those were not built for the street but the same thought process is still there.
Its like see what we can do ......
Next short term project please....
Maybe they had ADD before we knew what that was????
👍🏻
Those "430" hp L-88 427 Chevys actually made 570-580hp with headers. LS-7 454 made 600hp in stock trim with headers. Nothing could run with them back in the late 60s early 70s.
Clearly you haven’t been in a Hellcat or Redeye!
It probably picked up the few extra horsepower due to the better fuel we have today and also the engine dyno Dyno technology is way better than what they had back in the '70s and way more accurate over the analog that we had back then. So you can think of how many engines that we're probably underrated for their time back in the day.
👍🏻