L99 VS LT1 VS LT4-WHAT DO THEY FLOW?
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- เผยแพร่เมื่อ 26 ก.ย. 2024
- FULL FLOW BENCH RESULTS! 4.3L L99 VS 5.7L LT1 & LT4 HEADS. WHO FLOWS MORE? WHAT ABOUT VALVE SIZES OR CHAMBER DIMENSIONS?
MOST IMPORTANTLY, CAN THE BIG-VALVE LT1 OR LT4 HEADS BE RUN ON THE SMALL-BORE L99 BLOCK? CHECK OUT ALL THE FLOW NUMBERS (WITH FLOW PERCENTAGES), VALVE SIZES AND CHAMBER MEASUREMENTS TO SEE IF WE CAN (OR NEED TO) UPGRADE THE IRON L99 HEADS WITH ALUMINUM LT1 OR LT4 HEADS.
I want to see a big bang 5.7 LT1 build, with a twist. Crank up the boost on a stock 5.7 LT1 with ring gap, head gaskets a cam and the stock LT1 heads. Up to say 15psi. Then swap on the LT4 heads and run it at 15psi. Then swap some AFR heads on and run the same boost. Then shoot for the moon lol. A nice head comparison before finding the limit of the stock rotating assembly.
@@montgomeryhifiandreview5528 you must have been living under a rock. Stock lt1 has already been in the 1500-1800hp. 1320video has covered an lt1 stock block car that has ran 7.0 in the quarter mile.
@@montgomeryhifiandreview5528 yeah that's not the case. You can make well over 1000 HP with a small block chevy casting. Gen 1 or 2.
we've done 1000 hp lots of times on a stock Gen 1 block
@@richardholdener1727 back in the 90s I knew a guy boosting the lt1 past 1000. We hear all about them then, now when the LS came only hear how the old block couldn't ( when people did for pass after pass), and the preaching about cap walk and Mexican blocks and blah blah blah. I say LS was a great improvement, but people did crazy things before it, and somehow lasted
I really appreciate what you're doing with the LT1 style engines. There's not a lot of information out there unless you can afford some serious parts. I'm on a small budget so I'm looking for cheap and free diy mods
air foil, full exhaust, 1.6 roller rockers, cold air intake, full tune up, and a good tune should get any lt1 close to 300whp
@@Madmax.3 air foil cost 100 cfm blocks hole 240 back wheels max
300 with cold air intake
Great I'm gonna love those LT4 heads. Thanks Richard Holdener. Yea that be sweet if I could put LT4 on a 5.7 4 bolt block.
You can. A lot of NHRA stockers running LT1s use a 1st gen blocks. They bore a hole in the front of the heads for the water outlet.
The Corvette LT1 block is 4 bolt. But none of the fast LT1 cars run that block. The 2 bolt block is better for high horsepower builds. Because you can install aftermarket billet mains with splayed bolts. Something you cannot do to a factory 4 bolt block.
@@michaelallen2501 they are the same block and are a bit weaker than early blocks. Stocker racers use aftermarket gen 1 blocks and modify the heads.
@@bartpang well the fastest stick shift GM in the quarter mile uses a stock 1996 2 bolt LT1 block. De-stroked to 329 cubic inches and revving to 8500rpm, it makes north of 1600hp. No need for that aftermarket Gen 1 block. Look up Grubb Worm from Tick Performance. No Gen 1 or LS stuff there. All LT1.
@@michaelallen2501 It may have started life as a stock 2 bolt LT1 block but it's far from stock now.
Oh, BTW. My ???'s were regarding putting the LT1 head on as an LT4 probably won't work. Thanks AGAIN Richard for all you do! You always answer questions even before they're asked!!
Great I'm gonna love those LT4 heads. Thanks Richard Holdener. Yea that be sweet if I could put LT4 on a 5.7 4 bolt block.
@@naphi6769 I don't believe you were replying to me but here's my thoughts FWIW. The LT4 head is great and will bolt on to a 5.7l block as that is exactly what it came on in 1996. Yes, 1 year only. The problem you will have is FINDING LT4 heads! Not common and not cheap if you find them. What would be cool is if Rich did a flow test of the LT4 heads and an inexpensive Speedmaster/ProComp head as they be less expensive and MAYBE better?? Bare castings of course with a quality build package.
Most interesting channel I’ve ever found on TH-cam. I’m hoping it blows up and gets over a million. Richard someday I’d love some different cam dynos on an LT1.
we plan on doing cams
@@richardholdener1727 thank you!!!! I don’t think I’ve ever seen dyno numbers from LT1/LT4’s using different cams.
@@richardholdener1727 don’t leave the L83 out.....
It's rare to find someone showing you their flow bench. these are usually kept in a back room next to closely regarded racing secrets. Nice!
no secrets
That LT4 head DEFINITELY flows just as good as any stock cathedral port head 👍🏽
My stock LS1 GTO heads flowed well over 250 @ .500. Something like 255-256 I believe. All stock casting. The Lt4 did 239 @ .500. My stock GTO heads picked up flow at .600, the LT4 lost flow at .600. So they flow Just as good how exactly lol.
@@kennethpowers8995 I think your getting confused with 799/243 heads first of all. Stock LS1 head aren’t flowing 250cfm. More like 240ish. So yea I stand by my statement. And even if your comparing it to the 243 heads, 10cfm isn’t that big of a deal.
@@sstevocamaro The big deal is the Lt head drops off in flow whereas the LS head continues to pickup flow. Meaning the LS head can take advantage of cam profiles more than the LT head. And I’m pretty sure I was there when my heads were on the bench, and I actually have the flow sheet so your not going to convince me otherwise lol.
They actually flowed over 250, 254cfm to be exact. Radiused entry for the intake, 1 3/4 pipe was used for exhaust.
Edit- even if I was talking about a LS6/LS2 head, it’s still a cathedral port so it would still be valid, but I’ll post my LS1 goat flow numbers still.
My stock GTO castings flowed as follows;
.100- 65.2cfm
.200- 135.8cfm
.300-196cfm
.400-235.6cfm (i was nearly matching the LT4 head with only .400 lift)
.500-254.3cfm
.550-257.3cfm
.600-258.1cfm
Getting GOOD! I'm super excited to see the LT1 heads & TPI combo! That sounds like the ultimate real world budget build kinda thing. The 302 LT1 (w/a single plane) w/LT1 then LT4 heads would be awesome too to see as well
The 4.3 heads actually flow quite well for the displacement they’re feeding, much better than the so-called good heads of the 60s and 79s which were trying to support lots more cubes. The mid lift advantage of the LT1 heads may help the little engine, but my guess is the loss of compression will kill the gains. You show us this all the time when comparing 706 heads to almost anything else on the LS family. When you swap parts around to make a 302, the LT4 heads should do well, but I’d want to see the chamber volume reduced as much as possible-something you might not want to do to a spendy set of heads! Thanks for the interesting info, Richard!
From what I remember stock bore on a L99 is 3.736". If you want to run standard style heads, grab a stock bore 1-piece rear main seal 305 block and fit the 4.3s rotating assembly into the 305 block. Then test away with standard small block heads and intakes.
Can't wait to see the ported heads on there and manifolds..👍🏼 keep it up Rich
I thought about going the other direction, swapping on a LT head on a SBC, drilling water passages in the intake surface, and deck if needed,
Already done... Vortec heads, and they flow better than the LT-1
Sweet! Good to know my homeported LT1 heads beat the stock LT4 by 25 CFM. "intake" and 20 "exhaust" 😁
good to do flow comparison on the heads on the same bench, but it is certainly possible top better the stock LT4 heads with ported LT1s
ported lt4>ported lt1>lt4>lt1 cant beat a ported lt4 with the raised intake port ported they can flow over 300cfm on the intake and over 220cfm on the exhaust and its also good to flow on same bench at same time as rich stats your bench showed plus 25cfm but on richs bench it maybe less or more and vise versa but yeah must ported lt1s i see range from 240cfm-280 on the intake and 190-200 on the exhaust
I enjoy seeing these comparisons for a couple of reasons.
The LT-1 / LT-4 are the highest factory evolution of the original small block Chevrolet V8.
It's cool to see what they can still do considering they were originally designed, built, and released in 1955.
LS engines are great engines that are designed and built on the shoulders of what the engineers learned from the original small block.
Plus my '96 C4 has the LT-1 and it's really cool all the tricks GM used to make a lot of power in that day .
300 horsepower in a 3,100 pound vehicle is still fun to drive.
Another good video Richard. Thank you for sharing.
stock lt4 vs stock ls1 is drivers race the gen2 sbc is very underrated b/c it was only around for a few yrs and most jumped right to the ls stuff but im still whopping ls1 all the way up to the new lt1 the new cars come with a big problem WEIGHT there heavy 4000lbs heavy i have 3rd gens fbodys with lt1 and lt4s in them they all weigh under 3k if its a ls all motor w/o a power adder turbo or supercharged i rarely lose on the street same with dodge and ford the dodges are closer to 5000lbs in weight
Keep it coming Richard!! I definitely like to see the intake manifold test.
I wish you'd of been around 12 years ago when i was messing with a LT1 in a 95 Z28.... In the end i had a set of Loyd Elliot ported heads with 2.0 / 1.55 valves. it was a 355 and made 400hp at the wheels and i had a 250 shot on top of that! Nasty car!! LOL
I was around long before that-wrote my first magazine article in 1989 or so
I know they are super rare/expensive but getting lt-5 head flow numbers would be interesting even though nobody builds them.
I believe Mercury Racing still builds them.
But the lt5 is not a DoHC V8?
Why bother it is a 32 valve dual overhead cam cylinder head. It was used in gm flagship model as an option. There are simply not that many of them in existence. Lingenfelter did some porting on them years ago.
@@joaovitorsilvagohl682 That's right. Built by Mercury Racing. I was mistaken in my previous comment; Mercury Racing apparently no longer makes them. Try looking up 1990 Corvette ZR-1 LT5 for more information
Hey Richard, We entered a small Dyno competition at a local college (I’m a high school auto teacher) and the rules made us run an old style block but the head rule said any production sbc head, so we welded up the water port on a set of LT1s and drilled 3/4 holes out the back of the heads and ran the water back to the threaded holes on both sides of the water neck. We fully ported the LT1s and on our bench (Superflow 600) it flew around 260 cfm and near 80% exh (can’t recall exh cfm). We made 530 hp and 487! Ft lbs with a 355ci flat tappet and flat top pistons. We were 80hp above 2nd place! 😏. The following yr they sent us the rules “NO PORTING ALLOWED” 😕 so after a ton of searching we found a set of LT4s. We welded them up and did a nice valve job. They flew exactly the same as the ported LT1s! We went back that yr and made only 1 Horsepower less than the yr before!!! We then beat 2nd place by 100hp 😎 because they all had horsepower drops from the no porting rule.They canceled Dyno competitions after that lol Love your videos! Nelson Performance.
NICE JOB
Hey Rich, you need to put a pipe on the exhaust port when testing. It'll usually pull it up 20 cfm. It's the same as the radius entry on the intake port. Great channel. You've done lots of tests I've always wanted to do, especially the chassis dyno verses the engine dyno.
we ran a pipe on the exhaust
It might be a lot easier if you're having trouble dealing with the oddball LT1 stuff to get a roller 305 block and put the L99 rotating assembly in it - could run whatever heads and intake you want, that way.
I built a couple lt1's years ago. I'm excited for the tune port manifold test!
Please flow the heads with different size bore fixtures-smallest to largest. Also the Mr. Holdener Prototype adjustable FI intake! Thank you Richard.
Impressive numbers for the LT4 heads. That's every bit a good as the LS1 heads that replaced them.
You can always use a bigger bore head gasket to fit a bigger chamber head onto a smaller bore block but the valve size and valve lift is what's going be the limit on a small bore size relative to the other bigger engines that the bigger heads came off of fwiw
The chamber size of the l99 head could be a possible reason why the exhaust flow is so low
Working away nice it will pay off don't give up
Rich
Do an LS firing order on the 302 setup if you decide on a different cam than you ran in the 4.3
Rewire the cap and do batch fire injection unless you can tune it sequential
I got rid of my gen 1 stuff bout 3 years ago but had 0lanned the cam 0hase and was going to run the correct 350 cam and crank sensors and use an LS controller unlocked to tune it coil on plug
Dang thought I was going to get to see some new gen stuff. You know TH-cam is full of 6th gen camaro guys and a gen 5 lt1 bolt on or really anything to do with making more power with it would do really good!
The L99 seems to be tuned for mileage. Those numbers, if the theory is correct should bring the most economical package. Interesting!
Emissions and not only that but making power in the streetable RPM ranger smaller cubic inch requires smaller parts smaller parts in the cylinder heads etc
@@DSRE535 And when the parts are smaller, they also have smaller inertia, so it should rev higher and gain revs faster. A very good candidate for time attack etc.
Very good information.
Im in the process of modifying my dart 220 heads to work on n my lt1 block for many different intake options .
Good luck!
I have a LT1 swapped 83 elco this makes me excited to get my car running
I'd bet that flowing them on a fixture the size of the engine they'll be used on, will drastically change the results.
agreed
@@richardholdener1727 What size bore fixture did you use?
Richard there has to be a way to adapt a tractor turbo to ramcram it to some high velocity racing heads on an LS. You're the man that can make it happen.
RAMCRAM?
@@richardholdener1727 Yeah, a play on words based on the experimental Chrysler 392 RamCram hemi induction system, of which only 4 were said to have been made. The Chrysler Hemi Cross Ram intake manifold came out of that development. Any Nascar team engine tech should be able to Holman and Moody style cone port high velocity ports in some LS head castings, then just pair it with the appropriate off the shelf air gap short runner intake manifold. Any machinist should be able to mill it to accept one of the smaller Deere turbos. I'm thinking at least 9500 rpm on a prepared short block.
Car ramrod?
@@JesusSaves86AB You can if you want go ahead.
You can make a L99 into a 305 using the L30 rotating assembly. Both engines share the same pistons.
I'd love to have a set of LT4 heads and intake for my 96 Buick Roadmaster LT1. Parts for these engines are just too expensive for me. Especially right now
I love all this testing on head flow ! I am totally geeking out lol
Hey Richard, this is amazing information. I was wondering if it would be possible to explain how a flow bench works and what you are doing. I have heard of people say they have put heads on a flow bench before, but I have never really know the process for it. I am def curious about it.
Keep up the amazing content!
-Luis
Put the 4.3 l99 crank and rods in the 5.7 lt1 for a modern 302 cid and spin that SOB
He talked about doing this.
However, the valvetrain decides the RPM not the crank stroke.
I would have liked to know where exactly the between 500 and 600 lift that it lost flow and why?
yep
engine maths will answer ya questions.vavle curtain has a bit to say, port saturation point where valve lift is greater then port cross section so port becomes redundant.intake to exhaust valve percentage.port angle just say ha lift is 13mm because of port saturation its really only around 10 to 11mm.it goes on and on let's throw some variables in there to peace
I think a cool test to see would be a Carbureted car that you don’t need to AFR’s and run open heads no headers
It would have been nice to see the Flow of the Iron LT1 Head. I have 4 engines with those Heads.
Can you please build & test a L99 block 305 LT1. Will it make comparable power to the old DZ302?? Does the reverse cooling help with hp by allowing you to run more timing?? I love the other guys, other guys engines. Keep it up.
Ok, I believe we've all heard of "valve shroud". Is it true here with a small bore L99?? IDK, just asking if it's relevant??
Absolutely it's relevant for the L99, pretty much anything besides a hemi style combustion chamber whether it's overhead valve or overhead cam is going to suffer from the board being in the way of the flow path
@@DSRE535 Thanks for the reply and it's as I expected. I was looking for a reply/head flow test from Rich to confirm what I believe and what you stated. Numbers don't lie so a flow test on the L99 bore size with the LT1 heads would be nice to confirm. Also, food for thought is if an L98 TPI head would be better with a port and polish?? Still valve shroud? ONLY a flow test based on the L99 bore would be relevant. IMHO, the L99 is a waste of time, regardless of what you pay for it, anywhere. Thanks again.
What are you plans with the LT4 Heads? I'm getting my 383 LT4 Dyno'd on May 22nd with Ported GM LT4 Heads, a 236/244 cam, 12 to 1 compression, Jesel Shaft 1.5 Rockers, Edelbrock LT4 Intake Manifold, 58mm TPIS Throttle Body, Morel Lifters, Comp Valvesprings, Tool Steel Retainers, Lightweight 2.00 inch intake and 1.56 Exhaust Valves, Eagle ESP Armor Surface Treatment on the Crank and Rods, Melling Shark Tooth Oil Pump, and a LS style 24x ignition setup system from Torqhead. Anyway I'm very interested in any tests that you might do using the GM LT4 Cylinder Heads with the lightweight hollow stem 2.00 inch and 1.56 sodium filled exhaust valves.
Would love to see the smaller bore fixture and the .x50 numbers. Does it matter with the L99 if the carbon was cleaned off or not since the aluminum heads looked cleaner?
I hope you have seen tick performance lt1 camaro. They have pushed the 90's lt1 stock block to it's limits and it shows how under rated these engine are. I have made 800hp. On a stock lt1 with pistons only.
So you just had it bored and stroked and got 800 hp? No other modifications?!
@@justinfbabay no never bored or stroked. I honed and changed over to JE forged pistons and kept the stock rods and stock crank. I used a S480 turbo and ran 17psi of boost to make 800hp.
You should do a comparison on cam timing in a small block. Go from -6 degrees to +6 degrees comparing horsepower changes and rpm range.
I did that already-maybe i should do a video but it depends greatly on the cam you start with
Richard, let's see Edlbrock's Air Gap intake manifold and BBK's 58 mm throttle body on a stock 93-96 LT-1. I've never seen this any where..
The LT1 head was disappointing in that it only flowed 5% more than the L99 at .500 lift. But the LT1 really has a big advantage in mid-lift flow, about 17% at .300 lift. It was surprising that all the heads lost flow at .600, but just go with it. If you could get a series of cams that all have .500 peak lift, but successively longer duration, that would make for an interesting series of dyno tests.
And I think you need to flow all the heads again on a bore size close to the L99's, to show the effect of shrouding. People get all stressed out over shrouding, and it would be nice to put some real numbers on it. I don't get very excited about it because even though a small sector of the valve gets close to the cylinder wall, there is still the rest of the valve circumference that isn't.
why would you be surprised they lost flow at 600 stock cams are in the .450s the lt1 is vastly superior to the l99 look at that exhaust port
My L99 got mid to high 20s in my 95 caprice and not enough power to break the 4l60e. Great cruiser/lowrider drivetrain. I put 100k on it and sold it (70k to 170k) problem free.
To be honest i think with port work, and swap 1.94 intake valves in the l99 heads you can probably get in the 220-230 cfm flow range pretty easy, and get the exhaust side up to the 85% flow match
Keeping the small chambers will help keep the compression up(I would probably mill .020 off to gain a little more) vs, what you will loss with the lt1 head..
That compression is going keep low speed torque numbers up.. all of that and the right intake/cam combo, I think you can get 320-330hp out of this engine without having to spin it over 6k rpms
I agree-might do that to these heads with TPI intake
@@richardholdener1727 I know the tpi intake's will carry power to 5500 with a port work etc.
But most of those test done back in the day was always done on bigger engines, it maybe prefect on a 265ci engine and support power to 6k rpms and make a great torque curve from so little cubes haha
Right on
I like all the comparisons you do. I've got a 92 5.7 chevy in a K1500 makes a whooping 190hp. wow. looking to put vortex heads (from the junkyard or friend i'm helping do engine change) send to machine shop, a small cam for more torq, headers and getting rid of the TBI and going to either Carb or Fuel injection. Any thought or suggestions Engine has 60-80k mile.
yes on the intake, dual plane with 650 carb, 212/218 or so cam and Vortec heads with less than .450 lift or modify the valve guides
@@richardholdener1727 Thank you. love comparisons you do keep it up.
I believe the outer eight intake bolt holes will physically line up, but are at a different angle. People have used spacers to correct the angle and simply leave the inner four bolts out. It may be worth a shot for the engine dyno. The angle difference is ~17 degrees.
I do have a pair of iron LT1 heads that have been laying around. If you wanted to send me a shipping label, I could box them up and send your way for science. I have no use for them.
no position is also different on some of the outer 8 bolts
no need for spacer just drill and tap the lt1 heads to a sbc bolt pattern use a gasket for the lay out only need 8 bolts theres no coolant going through intake its just intake air doesnt need to be supper tight
Would be cool to do a SBC Head conversion on a LT, i say go for it!
l99 exhaust port is different than lt1 and lt4 first its not the D port and next the runner is only 62cc while the lt1 is 68cc and the lt4 exhaust port is 75cc
I'd also bet that the l99 head has a step just above the valve seat, that is a flow killer
BIG BANG 454....🙏
Yes!!
I also doubt you're going to see much of a power increase unless you really build that 4.3 to deal with some high RPM with a much bigger camshaft, intake flow exhaust flow it's all going to have to be a thought out combination in order to maximize that engine with the bigger heads in my opinion
I believe porting the l99 head would actually net the best results out of all of those heads in my opinion, similar to why the 706 and 862 had works the best on a 4.8 5.3 in a drivable RPM range
I agree with you on porting l99 head 👍
Keep the Gen 2 heads and modify the manifolds to work.
IMO even on the little 4.3 the LT4 heads will make the most power. They flow better and have smaller chambers than the LT1 heads. Given the same cam, compression and flow will give more power. The 265s smaller bore will slightly decrease the flow but not enough to negate the dramatic flow improvement of the heads. The valves open around 0.450" before they ever even clear the chamber. Use a thin steel shim style gasket for a B-car LT1 to keep the compression up and keep the gasket out of the chamber.
Love ya my brother
Put that lt4 head on the l99 and rev it up!
Hey are ever gonna finish with this engine I've literally been for this and what kind of numbers you can get with this engine and ALL the different combinations you could run please give us an update soon
COMING-WAITING ON TPI INTAKE
Can you do a sbc 24x reluctor swap compared to reg sbc and ls1
what number heads on lt1 and lt4 ?
also micrometer the exaust ports on both height and widthpf its feasable please
It'd be cool to see those 3 heads at .400" - .450" - .500" - .550" - .600" - .650" lift.
Have you done similar with 2v and 4v cleveland heads?
not the 2V
Personally I blame squirrels
I do as weell
🥜
Yes you do
When is the crank and piston switch coming? Lt1 with 4.3 crank and vice versa
Hi ! Want more L99 ! Have you forgotten ?
Wow the data is pretty interesting, I am asking for a friend because he doesn’t know, lol, in NA trim how much HP is 20 CFM extra capable of generating? Follow up question if you free up the intake flow do you lose torque?
I think it would be very interesting to see the L99 heads exhaust ported compared to the stock LT1 heads. My guess is in NA guise they’ll be similar so a person could run which ever they can get. If you throw boost at it then the unadulterated LT1 heads will probably win out. They probably had to choke the L99 up a little so it would give people a reason to buy the LT1 😉
20 cfm per cylinder can be worth 40 hp (or more or less)-depending on the power level and flow needs of the rest of the motor
@@richardholdener1727 was the flow test done on the L99 bore size and positioning?
@@thegdfp6447 no.
I want to see the Ford 3.4 sho V8 Big Bang. Man according to popular belief the 3.4 v8 should spin to about 40,000 RPM!!! 😂
that is high
I have read every article i could get my hands on and can't find what the 4.3 LT1heads CC at, pls enlighten me.
Also, i think it would be interesting to see what Cranking compression is between camshaft swaps Vince B.
We need to get you some donor cars to install all these gems you keep producing. One step at a time Killer Bee.
I have the Nova
"If the head don't fit, you must quit." (I got a million of 'em!)
Interesting video, interesting info.
If you're going to modify a Gen I SBC head to get more possibilities for intake swaps on the LT-1, which Gen I SBC head do you choose? That seems kind of like a rabbit-hole to me. Like something you could make a career out of, but how useful would it be to how many people, especially when there are lots and lots of LS motor for cheaper that make better power, better torque, better gas mileage, are newer, et cetera, et cetera? That's maybe more of a job for a Gen II fans' organization.
C'mon man! A hot rodder would say: "If the head don't fit, you must try harder,"
a very famous man said-we don't do these things because they are easy, we do them because they are hard
Hi Richard, could you please give us your two cents on the topic of wrapping headers to reduce under hood temps and improve scavenging.
Thanks for all your hard work.
definitely reduces heat-doubt you see much in flow improvement
go with jet hot lifetime warranty u can keep sending back when they rust the wrap reduces the life of the header and looks crappy imo
Im Game, let's see a sbc head on it with the modified water passage. The sky is the limit. I'm sure everyone would love to see
Seems pointless to delete the differences that make an LT series engine. SBC has been done.
If anyone is interested I have a set of ported LT1 heads from Golen Engins complete and ready to bolt on with the match ported intake. Along with a bunch of other performance parts for an LT1 just sitting around. Motor is out of a 93Z28, built top end with full bolt ons and a pcm tune it put down almost 415hp
How much are you asking? What else do you have?
@@poncoolride $750 for the complete heads and intake. I paid over $1200
@@poncoolride 2in intakes 1.56 ex. Beehive springs I believe. I have headers, aftermarket crab style distributor with msd wires and blaster coil, 236/242 comp cam(big cam), comp cam roller lifters and 1.6 rockers. It was basically a 383 top end. Probably a few other parts I'm forgetting.
@@515FLTRXS nice job little better build then my 503 baby cam 383 stroker but I make 425 hp 500 tq 96 ss impala I think I can get more out of her like you could with yours cheers!!!!
@@tta5891 It was a pretty good running car, a lot of fun especially with the 6spd. I probably left a little power on the table with the mail order tune. Instead of rebuilding it again I just decided to go the LS route. They're cheap and easy to get big power out of, a huge aftermarket parts supply and tuning options seem to be endless as well. The LT1 will always have a "cool" factor for me though.
You could have shown the numbers larger so we could read them.
But it's only a little motor
Great vid
Do you switch airflow directions when flow testing the exhaust?
Yes. The valving in the flow bench changes flow direction for intake versus exhaust ports.
yes-intake test sucks and exhaust test blows
You're a workhorse...
It the LT-1 combustion chamber overlaps the cylinder bore, is that not going to cause some serious disruption in airflow coming in via the intake valve?
it may-sometimes it just works-but I would like to test
@@richardholdener1727 Well, I suppose that's the only way to know for sure.
Rather than modify a GEN I SBC head to work on an LT1 bolt why not just drill and tap a set of LT1 heads for GEN I intakes?
correct you dont need all the holes either as there is no water going through the intake and hes only run time is the dyno i have a lt1 with the head drill and tapped for sbc1 for yrs no problems i only used 8 bolts to hold down a t ram manifold 4 on each side lt1 heads are about 300-500 for a pair most sbc gen 1 efi manifolds are worth 1k-5k
Why would airflow decrease at a higher lift? Is it a velocity issue?
port shape-cath ls heads often do the same thing
It’s caused by the “too big” area of the valve opening compared to the area of the port.
So in every head there is a certain point where this issue is.
Let say it like this, the factory heads are always a some sort of compromise, and that’s why people still today are tuning their heads.
Even the aftermarket ones. It’s a cause of having a target(s) to have on the build.
(Like how much flow on how much lift etc..)
I’m simplifying this but you get the idea.
From the factory the deal is:
1. You can have too small port (area) and too big valve (area)
2. You can have too big port (area) and too small valve (area)
3. You can have enough port area and enough valve area for what you’re looking for.
In the first the port area becomes the restriction, which causes that more lift wont make more flow.
In the second you’ll usually see poor low lift flow which improves in the middle lift and gains flow with more lift to the point where the too small of valve (area) is restricting the flow.
In the third you have a good baseline for a head for your application.
You can go with bigger valves and bigger port area if you need/want to.
Of course the valve shrouding and the combustion chamber size and shape is effecting to the flow characteristics too, but let’s not mix it to this now.
And velocity is it’s on topic too.
Velocity is good/needed on the low engine speeds and is not (in my opinion) a big thing to consider on race engines.
And it’s a big deal on a stock engines, cause emissions and sh*t.. 😃
Looking tired Richard, take care of yourself...
AFR makes a head for the 305 (same bore size) Maybe?
WATER PASSAGES
Cooling is over rated... lol
@@richardholdener1727 They were conventional sbc. 1.94x1.55 and 58cc if I remember correctly. discontinued I think
Trick flow made some 305 heads as well for the tuneport
Can you test the dump hump heads. 461, 462, 041, 291, 186, 492.
I have
O wow is the video on TH-cam? Where can I find all the information? Thank you!! Love the videos
Richard can I get a really quick answer which carburetor and ignition box would you suggest for a carbureted lq4 with the cam and spring upgrade using the 317 heads for a daily driver I appreciate any information you can tell me thank you
msd ignition with stock coils and a brawler 750
@@richardholdener1727 thank you for your Speedy reply I like every one of your episodes that I've watched keep up the great work
bring on the tpi intake
If you were to only port the exhaust side of a head would it change the HP drastically if it was a very restrictive exhaust side?
it might if that is the restriction
yes
Time to let the 4.3 go, no one is going to use this block in a serious application.
Except the guy running the super stock Caprice.
I checked at junk yards and lt1 is more expensive then ls stuff is this common? Because ls makes way more power
Not surprising, I spent a lot on my LT1 simply because it's what was originally in my Camaro and different than an LS. Very capable motor but yes this is ONE of the reasons it's not very popular anymore, consider this, u can make around 10-20% more power dollar for dollar with an LS.
our junkyards are all the same price for any v8-excpet BBC
@@richardholdener1727 no not here either i can get aluminum headed lt1 for 500 bucks if i looked with a 6 speed its at 1800 ls are 2k and up a stock lt1 vs stock ls1 is a drivers race you can drill and tap the heads or any sbc1 manifold and run a dizzy on a lt1 or lt4 and put it in any car with some minor changes ls needs more money an exhaust and ecu tune ect. to get going if your goal is under 500hp you cant beat a lt1 on price
i’m waiting for the tpi manifold. i think it will be good on the small engine. i don’t think the head upgrade is going to make a big enough difference to justify cost. i would port the l99 heads and send it.
aluminum lt1 heads are cheaper than porting iron heads they also flow really well on the exhaust side and are 50lbs lighter
tpi mani should make the most power to 4800 out of all the manis he will test doubt he will test hsr super ram or modified large tube tpi either
TPI will make power past 4800 on this 4.3L
@@richardholdener1727 more power than the lt1 and dual plane your gonna test?
I would be willing pitch in on a donation or something to help the Chanel seriously
They tell you to not mix up the 2 smaller bore lt1s and you did lol
its a 307 or 305 bored to 394 Ha Ha Ha
LT1 LT4 are the same Engine Block with 327 # on side of block lol
both 4 inch Blocks 350 means 4 inch bore 348 stroke
the 350 also has 70 thousanths bigger Dome exaust ports than the LT4 both Vertical and Horizontal
Also 162 intake ports the vet z28 heads have 175 cc intake runners
on the flow numbers Lt1 intake at 400 lift are 220 4.5 226 and go backwards at 500 and 600 are going lower thats what the dome exaust ports do is force vortec tumble
about 4900 rpm about 40 more horses hit
Dont know why your little lt1 is still gaining flow to 600
pretty good HP but Torque would be 100 less
the 350 heads flow 10 to 12 less than 195 LT4 through a 194 valve.
I just heard about a guy who ruined a set of LT1 heads putting 2 inch valves in them
350s respond realy good to 2 inch valves
smaller lt1 s Dont just opposite
Like you said LT4 heads on little motor not so good
LT4 is a 350 same as LT1
Hopefully, TH-cam does not block it but I did this to my SBC "or gen1" intake it was pretty easy with hand tools. I was able to run 10.8s on 93 gas NA and 9.9s on a 150 shot. 357CI th-cam.com/video/-o2lPfNY6kM/w-d-xo.html
Is it possible to run the opti and carb together as part of your combo?
could you do a AMC engine
like to