@@ZONES89RSwhat sold me on the ls was the fact that stock heads flow better than aftermarket heads on a small block Chevy. You can make the same power on a small block as an ls with a much larger cam and sacrificing street ability. The other great thing is the stock fuel injection system will support the 450 to 500hp ramp easily where as most stock fuel injection systems for small block Chevys you are in the 200 to 300hp range. If you go port injection and want decent power you have to spend about as much on the system as you would the whole ls swap.
@@Averagegunenthusiast yup, to beat a cam only LS1, I had to build a 383, porter aftermarket heads, and weigh much less. Just isn’t worth it for me to have fun when I have to replace everything in the engine to make less power than a cam only 6 liter
@@ZONES89RS it’s not just peak power either, it’s the area under the curve, my more mild 6.0 was faster through the whole rev range and in the vehicle it made a huge difference.
I have a 6.0 ls with a sloppy stage 3 and I chose to stick with the 862’s because I drive this foxbody on the street. I take it to the track a few times and the best I got was a 10.91 @ 125mph with a heavy 80e transmission. There will ALWAYS be something better than what you decide to build. But I built mine to drive. 95% of the time I’m under 5k rpm so that’s how I built it. Keep up the great work Richard!
Good sounding combo, I have a bmw 6.0 flat tops stock valve 706s but I did a little port work on it, ran 11.85 at 121 with street tires, and only recently discovered I was only getting 70% throttle, and have some sticky mickeys now I’m anxious to break it in the 10s
@@drivinwithdrew7676 good deal. I have a small bottle that helped me get to 10.91…. But my rear brakes are junk and I couldn’t foot brake it past 2400 even with a 2 step😝
Definitely made the correct choice with the 706 heads. I want towing power so I'll sacrifice that peak power for low end grunt. HP doesn't do me a bit of good on a wet boat ramp.
Im getting ready to use a set of CNC ported 853 heads on my 5.3 /383 build. I wasn’t looking for a certain number until I saw this video, so thanks for that. Lol
I put together a lq9 with a 218/224 600/600 112 with 241 heads. Started looking thru old posts on forums, and it's funny how much misinformation is out there. And there still is. People will still argue about this stuff even with Richard's testing. Great video and keep up the good work!
@@ZONES89RSHey I'm building a LQ9 if I put the 706 head's on it can I change the cam to the truck Norris cam and be ok not trying slap valve and piston and should I run a 5.3 head gasket may be a dumb question I'm just not sure 😁
@@my95chevy should be fine as that isn’t a very big cam. Works well for trucks but those heads are going to increase torque production. You won’t be disappointed
David Denman stated it well. In a street car, you are rarely going to see beyond 5K RPM. Rec Port are high flowing but only above 4,500 RPM. Engine Masters did the Cath vs Rec Port heads and came up with the results. Cath are great for the street or towing applications. If you have a 4,000 stall converter in a bracket car, rec ports are probably your best bet.
Anytime i have a question about a combo i look to see if Richard has already covered it, and glad he came through as usual! Looking at swapping out the 317's to 709's i have on another engine in the barn, for my 6.0, for added torque on my next project. I had a 99' TA about 12 years ago that made 484 whp 446 tq with a 6.0, fast 92, and trick flow 225's milled to around give or take a few 65cc and slightly smaller cam! Seeing the graph here, i might get the 706's worked, doesn't sacrifice too much low torque for a heck of a lot of hp/tq on the upswing! Great content as always!
From what I see on the dyno graphs the 706is going to be the head to use on a worktruck app. Every other head tested will out run the 706 if the converter is setup correctly. The combination that make the most average power over the USED rpm range will be the fastest. The TFS head would absolutely drag every other combo tested here.
A thing everyone over looks air speed which is important, Big ports can slow down air speed which can hurt low end torque, I been talking to my engine guy who is 1 of the best head porter in my country, I have seen him on his flow bench for hours with his piece of string watching where the flow is going, he has set many national records and 4 time national champion so he knows his shit, a Good example is Ford Cleveland heads where you got to run with plates in the intake, but its the turbo era where people throw on a turbo and screw up the turbo boost controller. I'm putting on a turbo but my engine will have Good N/A performance and some of the best parts I could find as well as turbo I've gone with the biggest LS I could get to spool up my turbo, I love watching you dyno testing with no BS I've learnt some stuff from you especially turbos which i'm no expert on them
I saw a video the other day where you whispered what the best ls head ever was, I can’t remember which one you said. But it’s had me searching for the video to watch again. Also I appreciate all your work In these videos! Keep it up your awesome!
The results speak for themselves. But it becomes a point where most don't have enough traction to use the torque down low in the rpm band, so having the HP up high and killing some low end torque works to their advantage. That's what I'm planning to do.
Wish you would have run the Fast intake on the 799 heads I feel it would have been closer to the rec ports. I have a LS6 with stock 243’s and cam, put a Fast intake on it and it’s gains were fairly significant over stock LS6 manifold.
There is no why about the ported square port, but we sure love to see that kind of info, lol TFS has velocity for sure. And I’m sure the combustion chamber was smaller to help as well. Always excellent videos my man.
Yoooo Richard!!! Made sure i hit the like first! Thanks for the valuable information! I used to go by sharpshooter by the way 😂 idk if you remember the name. But if not cool anyhow 😂. Rock on💪😎
Woop woop! We need to start going off a like under the curve number like say (( Hp = F(RHT) ~ a(RHT)=3300 b(RHT)=6600). Please excuse my short hand just rambling. Great test!!
Great video Rich! For N/A LS combos, There reaches threshold of displacement where the Rec port head begins to shine all the way across the RPM range. And that doesn’t happen until well into the 400’s for LS engines. A ported Rec Port head will see similar gains over its stock version similarly to the ported cathedral port heads over their stock versions. (Go figure?!)There’s obviously more variables that go into which is better for each application. What it comes down to when you start getting more and more extreme is the complete combination of the entire package; cam, port volume, cfm, valve size, all need to work together. There’s always a limiting factor in every setup though. Its typically in the head or exhaust restriction. The intake side just needs to supply enough air.
a ported rec port head won't see gains like the cath port heads did because they are already too big and have enough flow on the 6.0-you need lots of motor for rec port heads (especially ported ones)
@@richardholdener1727 I have a question… I’ve always been curious have you done a video with the fad of port polish and dimpling the heads? I remember that was a thing, but I never got any definitive answer when it came to any type of benefits when it came to doing that.
An advantage the 706 head has over the others that hasn't been mentioned yet is it experiences less valve shrouding flow restrictions. The two reasons are the smaller valve is easier to flow around at high lift, and the smaller bore spacing of the valve moves the valve further away from the cylinder wall. Both of these reduce restrictions at lower RPMs, hence the increase in low range torque.
As rich stated, being designed for the 4.8/5.3 bore it has the chamber issue but it just doesn’t matter due to the efficiency of those heads with a bigger displacement. I turn my stock stuff to 7500. So it really takes advantage of the bigger heads for that reason with my toys. A tow pig will just prefer the smaller heads all day since it would play under 4k most of the time.
As someone only interested in towing I have learned a lot from all of your videos. My first mistake was not researching all of this before buying a truck with a 5.3 and 4L60E. There's only so much you can do to improve low end torque. I'm currently debating between slapping in a 6.2l vs. cam, headers and turbo. In the end the motor swap is likely the most cost effective. I shopped 8.1l trucks for a while but finding a good one is difficult and the 6.2l makes more hp and just as much torque in stock form and better mpg. I have considered just upgrading the whole truck but practically everything is new or rebuilt throughout the drivetrain except the motor. Decisions, decisions.
Seems to me that a stroker setup for your 5.3 might be the best option. That way you get more displacement (and more torque) than the 6.2l, and you don't have to mess with any of the peripherals.
My 408 has to be making like 590! Unless the Trail blazer intake is holding it back. It is ported though whatever that’s worth. My Mamo 205s flow 300 and I have a cam that’s very close to the one in the test. It’s a 233/239 600 112. If I did it over I probably would have just used the LS3 heads so you get access to a killer intake for cheap.
Richard great video if only ford made good factory cylinder heads you could do a test on them I'm a ford guy but must admit cubic inch for cubic inch the ls engines are probably the best engines ever built
I agree! I’m not a total gm guy either. But I was looking for a great candidate to put a fuel injected big block with overdrive in my 1978 F350 (on a budget) unfortunately I had to go with a GM powertrain if I wanted to make decent hp/TQ on a budget. So now I own 2 fords with GM drivetrains. Fords make great platforms, in the vehicle department….. but not really in the engine department.
Got me a 5.3 getting 706 heads ill try to work out a all round good range cam for it thks for your videos bought the injection from megee racing nice intake and aces controls
Good video. The rec ports become FAR more efficient with turbo applications where your stuffing 2-3 the air volume through the heads. And as im sure other guys mentioned you can mill 0.030 off em and get back some compression (which increases power EVERYWHERE). Get back all that low end tq you lost and gain even more up top. I would really like too see you run some ac delco cnc ported ls9 heads. Factory titanium intake valves, factory sodium filled exhaust valves, factory 350cfm heads.
He has another video comparing cathedral vs rec when turbocharged and the gap is exactly the same but multiplied by boost. The rec isn't any more efficient when turbo
@Richard Holdener Yes but with an 80mm the rec ports are far less of a restriction than cathedral ports. Seen L76 make 930hp on 15psi. Stock rec ports. Modest turbo cam, (s2 btr turbo cam iirc.) Thats just not happening with even 243/799 heads.
@@Saddedude that isn't how it works he has videos showing the results The heads arent a "restriction" If the rec ports make 20hp more na they make 40hp more at 15 psi The turbo just multiplies the na result the behavior is exactly the same
I did an LS swap in my 00 escalade. LS1 5.3 punched out to 5.7, 243 heads, beehive springs, built 4l60e and a Summit Stage 3 cam. Waiting to do 4:11 gears and tbss intake, but as it stands now, torque definitely isnt an issue. Probably will replace the cam with a torque cam or truck norris, becuase im never at the 5000rpm to use the horsepower. Unless youre racing, who the hell gets up to 5500+ rpm
I still like the LS3 head/ intake combo on a Mild 6.0. easy 500WHP combo without the expense of a CNC head and... AND I'm usually working on LQ4/LQ9 6.0's with a kabilion miles the 100,000 mile 317 heads need a valve job anyway. a Dorman LS3 intake and a pair of Blueprint LS3 heads is a solid budget option just about any Cam/Tune can snezze on in and make 500whp
The blue print heads are still 1200USD each so with to doorman intake and heads it's close to 3k just for the heads and intake. so its not the cheapest way to make 500hp when you can port the 706 and still get there. Is less time tho🤷♂️
@@mackenziehutchison4838 WOW i just price checked that there are lots of $600-900 LS3 options. scratch the blueprint. the GM part # 12675871 are $800 ish and RHS is under $700ea that's new pricing, if your local machine shop can beat that for a Tank/ flux/ lap & seat pressure check good for them mine can't.
@@richardholdener1727 mine on one dyno mild lq9 with ls3 topend made 414hp on one dyno. Was disappointed. Got it returned on another dyno but they refused to run it in 1:1 because I had 2.73 gears and base was 370 and retuned 395hp
Love your videos, and I've watched all your 6L videos(I think). I have a stock LQ9 in a denali. If I did 1 3/4 headers, 706 heads, what cam would you recommend for a daily driver/work truck, and how much power do you think that would add?
For street driving it’s all about the low end of the torque curve. The 706 heads have the smallest chamber and that’s the biggest reason they excel. The TFS 225s likewise have 65 cc chambers (ie, smaller, just not as small) and beat the rec port heads in part due to the increase in compression. I think the ports are more refined to take advantage of the 13.5° valve angle, too. They’re just better-but my engine came with 823s…I’ll stick with them for now.
your not wrong but if you look at the 799 Vs the 317 head, the ONLY difference is the combustion chamber volume....... you can easily throw more timing at a 317 head than you ever could on a 799 but this was a Head VS Head test. same goes for Rec Vs Cat port. you can fix the minimal low end losses with some timing and fuel. at the end of the day we are splitting hairs 8lbft here or 19hp there. I can get LS3 heads and intake attached to a running short block at Copart 2 or 3 times before I pay for the TFS 225's
Also worth noting, the expensive trickflow heads required an expensive FAST intake to make the HP/TQ gains. Whereas, Mr Holdener has proven the (cheap) truck rectangle port intake to be equal to the LS3 on (cheap) rectangle port heads
I don’t understand why compression ratio is not talked about more. The 706 heads have tiny chambers. That’s why they work well in these applications. Same with all these cam swaps. Put these large cams in otherwise stock engines and the results aren’t nearly what they could be if the compression was straightened out.
chamber volumes were provided in the video and compression is not what provided the change in power offered by the 706 heads, and the cam run on this motor was run with a stock bottom end and stock heads!
The greatest expense is usually a stroker build. Using new parts hen ending custom balancing. And many time over boring the factory block. But with chinese turbos and e85 the game has changed. Bloodviking
I have the mildly ported 823's in my LS2 with LS9 cam with a Turbonetics 78 mm with a 1.15 AR housing. What do you think about this combination for power?
When running these combinations, changing heads, cams, intake ect, do I need a Holley hp system or dominator? Or can I use stock computer and turner. Or is it as simple as getting it dyno tuned? I want to know before pulling my 2002 Cadillac Escalade apart. Thanks!
@Richard Holdener come on tell me the secret combination. I know the 706 works well because the compression goes up and the downside to the 317 is the compression dropping. Would the 317 be any better than the 317 if the compression was the same my changing the piston?
@D BAIRD from what I can recall from other videos, the only problem with this is you can only mill so much and dome up so much as well until you start running into available valve clearance issues, lift on cams as well. So to me it seems like you are just money and time ahead going to the 799 of aftermarket heads. Instead of trying to figure out that magical combination of pistons, milling, cam specs, rocker ratio, pushrod length, and vavle train components.. just slapp on a set of 799's and half the problem of the 317's is fixed
@Mason Campos with a compression calculator the compression comes to 10:5 :1 without modifying the head with a 5cc flat top because of the compression height of dss piston. I was wondering if that would be and better than the 706 with a dished piston?
This has been proven time and again by Richard and on Engine Masters, whatever your combination produces NA, boost will only amplify it. Build the engine for your purpose. If you want to throw a turbo on your street car, you don't need rec port heads. If you are throwing a turbo on a "race" engine, turning high RPM, rec port may be the way to go.
I remember some of these comparisons from other tests you've done. I'm sort of convinced now that it must be the camshaft that makes my current combination such a dud. If only I had unlimited dyno time and wasn't daily driving my truck... I would absolutely swap in a different cam and give the 862s another chance.
@@daviddenman7479 It doesn't make much power. Even Richard has said something seems off. I've offered to share my tune file with anyone that wants to have a look. It's an LQ4, 862s, TSP CHOPacabra cam, TBSS intake, 92mm TB, headers, exhaust, CAI...has all the supporting mods. Tuned on 93 octane, etc. It made 336HP/336TQ 4L80E, 3000 stall. My old cam and 317s made 327/369 on 87 octane. I think my next place to start chasing things is a compression and leak down test. If that checks out good, it's time to blame the cam as being a poor choice for this application.
@BlueCollar Hotrods I'm just curious have you checked pushrod length? Don't think it should be an issue with that cam, but different heads on different motor sometimes can throw things off.. just my opinion, I really feel 862's are a restrictor for 6.0L. But even so it seems like you'd have to have multiple misfiring cylinders to have those numbers.. good luck figuring it out
@@masoncampos7043 I didn't. Block and heads are untouched, I threw in a set of stock pushrods. The valvetrain isn't noisy, etc. Aside from the weak power numbers, it runs good and is reliable.
Compression helps low rpm power 99% of the time . A small chamber 5.3 head can get you in trouble on pump 93 a lot quicker than the larger chamber head too, on a big bore ls. Its trade offs , but its important to make people understand the real world consequences of the switch . I hear people dogging 317 heads all the time , saying they won't make power . Its true that they suck on the wrong app , just like every single other thing that uses physics to function . A 71cc chamber on a small bore engine will be lazy , just like a tiny chamber headoin a big bore with make great power but be knock sensitive on pump gas.
Hey Richard, Sorry for responding to an old video. I have an Lq4 I’m prepping for a build. I found a set of 862 heads for $80 so I’m leaning towards swapping the 317 heads for those. This engine is going in an e46 bmw for a drift build. Would the truck Norris cam kit be a sufficient option for my application for should I be looking towards a bigger cam like a SS2 or SS3? Thank you for your help as always
Hi Richard hope all is well Im into rebuilding a 383 stroker using 5.3 block just revisited this the 5.3 engine has 706 from your video on 5.3 stroker build you use ls6 heads . My project is torque from researching your test the 706s have good low end torque witch is my goal Your thoughts please Cheers Aaron New Zealand
I've seen people spent crazy money on good heads on boosted engines just to make a lousey 30 to 40 hp. Budgeting is wise. 4k for a set of heads that add 70 hp is not great when you could add twin turbos for 400 dollars and get 200 to 400 hp from boost alone.
I always thought cathedral port heads were factor great from the start they had to make out the gen1 smallblock so there you have wonderful content and it would be nice to do it with 4150 style intakes and holley or atomic efi.
I think that was because back in the day EFI was VooDoo/ witchcraft and guys where clawing at carb options and even distributor options. as the tech has advanced and EFI has become less of a dark art.
Terminator x has lowered the efi barrier of entry to be cheaper than a carb for the LS. Also, search out Joe Simpson and you’ll find dozens of tuning videos to make it very easy to do it yourself.
im in need of help. i have a 04 ls swapped 5.3, in a 88 cutlass. the car ran great for about two months, then one day it just shut off,, after checking the system[wire harness] i found that the two power wires that hooks to the starter and the crankshaft sensor wire had burnt into the header, so i bought a new stand alone wiring harness, once i finish installing the harness, the car started up but it had a really bad vibration so i shut the car off and rechecked behind myself to make sure everything was in its place as it should be, which it was so i restarted the car [still had a bad vibration] but it ran for 3 mins then shut off, in would not start again. so i went to checking the possiblities , i check fuel in which its getting 59 psi of fuel. i check all my grounds , they all had good connection, i check to see if the ignition was getting 12v and constant 12v which it was, i check to see was the the coils getting ground and 12v which they both was but i wasnt getting any sparks, so i check the crank and cam sensor with they was both getting power so i replace them just in case and still no sparks.. can anyone please point me in the right direction. on how to fix this..
What do you think about the TFS 225 heads vs a rec port on a 408 stroker? Seems like this TFS 225 head is a solid choice. I'll be running upto maybe 7200-7300 rpm max and an occasional 200 shot. Seems like the tfs 225 and fast LSXR 102 with the right cam could be what I go with. Thoughts?
@@richardholdener1727 do you think a 408 would have more consistent power throughout the 3800-7300 rpm range with the TFS 225 and fast lsxr or would it benefit more from a rec port head and intake setup?
Hey Richard, have you ever dealt with milled heads (might have missed those vids). a good topic may be how much can you mill from a cyl head before needing a different length pushrods. im stuck in that dilemma now. i want to mill the stock 823 heads (bought it used from junkyard) but already have sloppy stage 2.
@@richardholdener1727gotcha. Im not even trying to mill for conpression moreso the fact that im buying used heads so to make sure its flat maybe even mill .005 but idk how much that affects the stock pushrod length. But would also be a decent topic to explain how to check all that out.
.005 changes nothing on pushrod choice-and milling the head a given amount changes the pushrod length requirement by that amount. But since you have more than .030 (for example) of adjustability of standard travel lifters, there is often no need to change pushrods.
Does the VVT on the L96 (and its rec port heads) make up for the low end torque deficit perhaps? Since the L96 was the last hurrah of the LS engines in the HD trucks you'd think they would put their best combination together. I think the stock 360 hp rating on the L96 is very conservative.
Trucks have crap intake and exhaust. A L86 has the same; heads, cam, compression as a LT1. The difference is intake and exhaust manifolds, intake air ducting, exhaust system and tune. Thats it. There is a 35 or 40hp difference between a L86 and Lt1. The L99, the 6.2l VVT from Camaro SS with auto has 400hp. That's 40hp up on the L96. That 360hp rating is probably a little conservative but I doubt more than 10hp. The trucks, especially the 2500/3500 have a really restrictive intake and exhaust system that keeps things quiet. Even the L8T has the same heads and cam as the LT1 and a little less compression. The manifolds, ducting and exhaust drags that down to 401hp...
I haven't look through every comment but can I still use the 706's if I use the cheap 87 octane on a daily driver and still get all those benefits of the higher compression. Does that change things at all being 87 is much cheaper than premium. I'm talking daily driver and a which one would be best when cost to drive is considered.
Are the head gaskets go bad often I have a 5.3 with 706 heads put in my swap and I have a leak in the head getting head gases in my cooling system should I just change gaskets are heads also it has 706 cathedral heads came out of 2004 Chevy Tahoe I believe ! What is best head gaskets to use on the 4 kid show string budget !!!
I have a question you might can answer if you see this… I have a stock ls2 so flat top pistons currently running 799 heads but they are worn out and I have some stock 706 heads that I would like to do a quick swap with.. but my concern is compression!! I’m on a 93 tune and would like to stay on that being my daily vehicle. Will this be okay?? From what I read it’ll be 12:1 static CR which I’ve been told is insane.. but want to know your opinion! And if you have anything else you feel like I should know please tell me
Hey Richard I have a lq9 I'm getting refreshed and I just picked up some non-cashtech 706 heads what cam, pushrods, springs and what head gasket do I need to put it together
Got a 2000 c5 vette, 6speed LS1 5.7. The heads on the motor are 241, I’m planning on swapping them out for 706 heads that I got from a 5.3. I’ve seen your test and notice how the 706 heads outperformed all the other heads. My question is, do I need to do anything to the heads to make them fit on the LS1? I’m planning to go mid to high power close to 500HP so are the 706 a good choice?
Correct me if I'm wrong but I thought the 706 vs 799's on the cathedral video did the opposite on the 5.3. With the 706 making more peak, and 799 low end power?
@splitface454 yeah I just rewatched the short version of that. I'm guessing the small bump in compression is not as beneficial as the flow of the 799 on the larger c.i. motor. Wich is why I choose them for my 6L
I have a 6.0 out of a 02 escalade going into a c10. going with a truck Norris cam. My question is my engine has 317s on it is it worth the upgrade to get 799s if I’m just replacing stock with stock no work other than springs and seals?
What I wanna know is do you think the 706 heads would gain much torque on a stock 6.0 you know for helping out a big heavy Denali XL, I know this test probably has never been done I’m just wondering if I could still run on 89 octane or less
My dad has 799s on his 6.0 with a stage 1 BTR towing cam. It’s a torque monster! He drags logs out of the woods for his sawmill with it. It’s a crew cab 4x4. The thing sounds crazy under load with a big tree dragging behind it 😂
@@richardholdener1727 thank you, I’m only interested in power off idle to 5000 RPM or so, what kind of fuel do you think I’m gonna have to run if I do the swap ?
@@richardholdener1727 Thanks Mr. Holdener. I'm going back and looking at all the videos on the LS and getting all the info I can on them especially the 5.3. I'm a Johnny come lately on the LS. Thanks for the vids and the info.
Hey rich, I’m I turned to start a 408 stroked. Btr 233/248 what heads should I go with n/a? I think I heard you saw if plan on running boost I should keep my 317s but can’t get why?
@@richardholdener1727 600+hp I saw one that you had used afr 245 heads but didn’t work right for that combo. Would it still be a good idea to run them for future boost?
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Always amazes me how good the "bad" LS heads are.
Yup...we are spoiled these days.
And somehow we have SBC guys claiming a LS is a bad engine.
@@ZONES89RSwhat sold me on the ls was the fact that stock heads flow better than aftermarket heads on a small block Chevy. You can make the same power on a small block as an ls with a much larger cam and sacrificing street ability. The other great thing is the stock fuel injection system will support the 450 to 500hp ramp easily where as most stock fuel injection systems for small block Chevys you are in the 200 to 300hp range. If you go port injection and want decent power you have to spend about as much on the system as you would the whole ls swap.
@@Averagegunenthusiast yup, to beat a cam only LS1, I had to build a 383, porter aftermarket heads, and weigh much less.
Just isn’t worth it for me to have fun when I have to replace everything in the engine to make less power than a cam only 6 liter
@@ZONES89RS it’s not just peak power either, it’s the area under the curve, my more mild 6.0 was faster through the whole rev range and in the vehicle it made a huge difference.
I have a 6.0 ls with a sloppy stage 3 and I chose to stick with the 862’s because I drive this foxbody on the street. I take it to the track a few times and the best I got was a 10.91 @ 125mph with a heavy 80e transmission. There will ALWAYS be something better than what you decide to build. But I built mine to drive. 95% of the time I’m under 5k rpm so that’s how I built it. Keep up the great work Richard!
Are you running stock bottom end and pistons?
@@masoncampos7043 absolutely!
That's a strong running combination. What converter does it have? And what does it weigh?
Good sounding combo, I have a bmw 6.0 flat tops stock valve 706s but I did a little port work on it, ran 11.85 at 121 with street tires, and only recently discovered I was only getting 70% throttle, and have some sticky mickeys now I’m anxious to break it in the 10s
@@drivinwithdrew7676 good deal. I have a small bottle that helped me get to 10.91…. But my rear brakes are junk and I couldn’t foot brake it past 2400 even with a 2 step😝
Definitely made the correct choice with the 706 heads. I want towing power so I'll sacrifice that peak power for low end grunt. HP doesn't do me a bit of good on a wet boat ramp.
Love these videos. I just made 463 hp and 425 TQ from my LS1, fast 102 intake, BTR stg 4 cam, custom headers and stock 706 heads! Love them.
Nice work!
My 2011 4.8 has the 799 heads and traiblazer intake from factory. I put a 6.2 crank and 5.3 rods in it. Good runner.
Im getting ready to use a set of CNC ported 853 heads on my 5.3 /383 build. I wasn’t looking for a certain number until I saw this video, so thanks for that. Lol
I put together a lq9 with a 218/224 600/600 112 with 241 heads. Started looking thru old posts on forums, and it's funny how much misinformation is out there. And there still is. People will still argue about this stuff even with Richard's testing. Great video and keep up the good work!
It’s normal. People believe what they will. I try to recommend smaller cams and guys don’t wanna hear it. So let them do whatever
@@ZONES89RSHey I'm building a LQ9 if I put the 706 head's on it can I change the cam to the truck Norris cam and be ok not trying slap valve and piston and should I run a 5.3 head gasket may be a dumb question I'm just not sure 😁
@@my95chevy should be fine as that isn’t a very big cam. Works well for trucks but those heads are going to increase torque production. You won’t be disappointed
@@my95chevy you have to use 6.0 gasket because the piston size is different than a 5.3 i have a lq4 with 706 head I built last year
@@mike-wz9bb I was hearing different so I wanted to make sure thanks 👍
I've been waiting for this one!!
David Denman stated it well. In a street car, you are rarely going to see beyond 5K RPM. Rec Port are high flowing but only above 4,500 RPM. Engine Masters did the Cath vs Rec Port heads and came up with the results. Cath are great for the street or towing applications. If you have a 4,000 stall converter in a bracket car, rec ports are probably your best bet.
Anytime i have a question about a combo i look to see if Richard has already covered it, and glad he came through as usual! Looking at swapping out the 317's to 709's i have on another engine in the barn, for my 6.0, for added torque on my next project. I had a 99' TA about 12 years ago that made 484 whp 446 tq with a 6.0, fast 92, and trick flow 225's milled to around give or take a few 65cc and slightly smaller cam! Seeing the graph here, i might get the 706's worked, doesn't sacrifice too much low torque for a heck of a lot of hp/tq on the upswing! Great content as always!
Thank you sir Richard for all that you do!! I know how much work it is just wanted to say thank you
I appreciate that
From what I see on the dyno graphs the 706is going to be the head to use on a worktruck app. Every other head tested will out run the 706 if the converter is setup correctly. The combination that make the most average power over the USED rpm range will be the fastest. The TFS head would absolutely drag every other combo tested here.
And this video is why you’re my favorite TH-camr!!!
706 over 799s for me as it may help spool rate. Then you can make up the few hp up top but adding boost.
I like finding 08/09 GM trucks with a 243 on one side, and 799 on the other side, I saw the third one last week on an LC9 Sierra.
I have seen that
A thing everyone over looks air speed which is important, Big ports can slow down air speed which can hurt low end torque, I been talking to my engine guy who is 1 of the best head porter in my country, I have seen him on his flow bench for hours with his piece of string watching where the flow is going, he has set many national records and 4 time national champion so he knows his shit, a Good example is Ford Cleveland heads where you got to run with plates in the intake, but its the turbo era where people throw on a turbo and screw up the turbo boost controller.
I'm putting on a turbo but my engine will have Good N/A performance and some of the best parts I could find as well as turbo I've gone with the biggest LS I could get to spool up my turbo, I love watching you dyno testing with no BS I've learnt some stuff from you especially turbos which i'm no expert on them
I saw a video the other day where you whispered what the best ls head ever was, I can’t remember which one you said. But it’s had me searching for the video to watch again. Also I appreciate all your work In these videos! Keep it up your awesome!
the best one is the one you have
@@richardholdener1727Early iron heads on my LQ4… I think Ill switch😂
I like the low end torque numbers from the 706's. Kind of what I expected with the higher intake velocity they offer.
The results speak for themselves. But it becomes a point where most don't have enough traction to use the torque down low in the rpm band, so having the HP up high and killing some low end torque works to their advantage. That's what I'm planning to do.
Gearing would help get it into your power band too. I put 3.89 gears in my 67 mustang.
Exactly, spinning ain't winning. If it's a daily driver truck though you generally want as much low end power as you can
Love your new formatting...shortening the video but putting a concise and large amount of info on the video.
Thank you!
this is not new format-been doing it for over 2 years now
@@richardholdener1727 He probably hasn’t tuned in since you had the grey backdrop or the treehouse lol
just plain ole good tech to have info about, thanks Richard!
Wish you would have run the Fast intake on the 799 heads I feel it would have been closer to the rec ports. I have a LS6 with stock 243’s and cam, put a Fast intake on it and it’s gains were fairly significant over stock LS6 manifold.
There is no why about the ported square port, but we sure love to see that kind of info, lol
TFS has velocity for sure. And I’m sure the combustion chamber was smaller to help as well.
Always excellent videos my man.
Good test that many struggle with.
Yoooo Richard!!! Made sure i hit the like first! Thanks for the valuable information! I used to go by sharpshooter by the way 😂 idk if you remember the name. But if not cool anyhow 😂. Rock on💪😎
6 liter with 706 heads and a Truck Norris cam should move things fairly easily.
Those heads are badass for towing purposes. 😊
Woop woop! We need to start going off a like under the curve number like say (( Hp = F(RHT) ~ a(RHT)=3300 b(RHT)=6600). Please excuse my short hand just rambling. Great test!!
average hp or torque or both is more than sufficient, but the curve already tells you what you need to know to decide
@@richardholdener1727 Noted. What kind of gains would you guess from the light weight valve swap?
Great video Rich! For N/A LS combos, There reaches threshold of displacement where the Rec port head begins to shine all the way across the RPM range. And that doesn’t happen until well into the 400’s for LS engines. A ported Rec Port head will see similar gains over its stock version similarly to the ported cathedral port heads over their stock versions. (Go figure?!)There’s obviously more variables that go into which is better for each application. What it comes down to when you start getting more and more extreme is the complete combination of the entire package; cam, port volume, cfm, valve size, all need to work together. There’s always a limiting factor in every setup though. Its typically in the head or exhaust restriction. The intake side just needs to supply enough air.
a ported rec port head won't see gains like the cath port heads did because they are already too big and have enough flow on the 6.0-you need lots of motor for rec port heads (especially ported ones)
@@richardholdener1727 They see BIG gains on porting the exhaust ports. Intake ports just need a clean up.
@@richardholdener1727 I have a question… I’ve always been curious have you done a video with the fad of port polish and dimpling the heads? I remember that was a thing, but I never got any definitive answer when it came to any type of benefits when it came to doing that.
SBC and BBC , LS the most used engines in all forms of racing, dependable,cost effective, horsepower.
An advantage the 706 head has over the others that hasn't been mentioned yet is it experiences less valve shrouding flow restrictions. The two reasons are the smaller valve is easier to flow around at high lift, and the smaller bore spacing of the valve moves the valve further away from the cylinder wall. Both of these reduce restrictions at lower RPMs, hence the increase in low range torque.
the chamber inside diameter is actually smaller on the 706 so it has valve shrounding in the chamber too
As rich stated, being designed for the 4.8/5.3 bore it has the chamber issue but it just doesn’t matter due to the efficiency of those heads with a bigger displacement.
I turn my stock stuff to 7500. So it really takes advantage of the bigger heads for that reason with my toys.
A tow pig will just prefer the smaller heads all day since it would play under 4k most of the time.
As someone only interested in towing I have learned a lot from all of your videos. My first mistake was not researching all of this before buying a truck with a 5.3 and 4L60E. There's only so much you can do to improve low end torque. I'm currently debating between slapping in a 6.2l vs. cam, headers and turbo. In the end the motor swap is likely the most cost effective. I shopped 8.1l trucks for a while but finding a good one is difficult and the 6.2l makes more hp and just as much torque in stock form and better mpg. I have considered just upgrading the whole truck but practically everything is new or rebuilt throughout the drivetrain except the motor. Decisions, decisions.
Seems to me that a stroker setup for your 5.3 might be the best option. That way you get more displacement (and more torque) than the 6.2l, and you don't have to mess with any of the peripherals.
6 liter and don’t look back. The extra 2k for a 6.2 isn’t worth the whopping 15-20 more HP/torque in my opinion.
@@ZONES89RSI😮 agree go with a forged stroker if u can afford it a cast one if u can't. 💨
My 408 has to be making like 590! Unless the Trail blazer intake is holding it back. It is ported though whatever that’s worth. My Mamo 205s flow 300 and I have a cam that’s very close to the one in the test. It’s a 233/239 600 112. If I did it over I probably would have just used the LS3 heads so you get access to a killer intake for cheap.
Thank you for the heads line up Richard! Which One of these stock heads produced the highest peak torque on the 6L?
the rec ports
Damn, I expected more than a peaky 10hp gain from the 799’s. I bet they’ll do better being milled for compression tho.
Richard great video if only ford made good factory cylinder heads you could do a test on them I'm a ford guy but must admit cubic inch for cubic inch the ls engines are probably the best engines ever built
I agree! I’m not a total gm guy either. But I was looking for a great candidate to put a fuel injected big block with overdrive in my 1978 F350 (on a budget) unfortunately I had to go with a GM powertrain if I wanted to make decent hp/TQ on a budget. So now I own 2 fords with GM drivetrains. Fords make great platforms, in the vehicle department….. but not really in the engine department.
"Pushrod" engine. That's the key.
Imagine the work involved putting ford heads on a Ls properly
Got me a 5.3 getting 706 heads ill try to work out a all round good range cam for it thks for your videos bought the injection from megee racing nice intake and aces controls
lots of cams to choose from on the channel-pick the one that makes the power you want
Richard, love the content. Do 706 heads need any machining or special attention when going onto an LQ9 bottom end?
They do not, literally bolt them on and go.
I know you're a busy man but i love your content and thought we could use a laugh. Built 2 engines now off your info recommendations
What head gaskets did you use with the 706 heads?
Good video.
The rec ports become FAR more efficient with turbo applications where your stuffing 2-3 the air volume through the heads.
And as im sure other guys mentioned you can mill 0.030 off em and get back some compression (which increases power EVERYWHERE). Get back all that low end tq you lost and gain even more up top.
I would really like too see you run some ac delco cnc ported ls9 heads. Factory titanium intake valves, factory sodium filled exhaust valves, factory 350cfm heads.
He has another video comparing cathedral vs rec when turbocharged and the gap is exactly the same but multiplied by boost. The rec isn't any more efficient when turbo
boost just multiplies what is there-doesn't matter rec or cath port
@Richard Holdener Yes but with an 80mm the rec ports are far less of a restriction than cathedral ports.
Seen L76 make 930hp on 15psi. Stock rec ports. Modest turbo cam, (s2 btr turbo cam iirc.)
Thats just not happening with even 243/799 heads.
@@Saddedude that isn't how it works he has videos showing the results
The heads arent a "restriction"
If the rec ports make 20hp more na they make 40hp more at 15 psi
The turbo just multiplies the na result the behavior is exactly the same
@Chip Currey yeah so a 40-50hp gain is a big deal. Now lets talk 30 psi
I did an LS swap in my 00 escalade. LS1 5.3 punched out to 5.7, 243 heads, beehive springs, built 4l60e and a Summit Stage 3 cam. Waiting to do 4:11 gears and tbss intake, but as it stands now, torque definitely isnt an issue. Probably will replace the cam with a torque cam or truck norris, becuase im never at the 5000rpm to use the horsepower. Unless youre racing, who the hell gets up to 5500+ rpm
I’m running a tsp 216/220 cam with full bolt ons and 373 gears. I rev it out to 6300 and that’s in a lm7 5.3
Ls swaps are certainly the most popular thing since the chevy 283 came but unless you boost an ls it's pretty much capped at about 530 hp.
Bloodviking
530 is great power especially if you using as a daily
Gawd I love this channel !!!! 🎉🤘🏼😛
I still like the LS3 head/ intake combo on a Mild 6.0. easy 500WHP combo without the expense of a CNC head and... AND I'm usually working on LQ4/LQ9 6.0's with a kabilion miles the 100,000 mile 317 heads need a valve job anyway. a Dorman LS3 intake and a pair of Blueprint LS3 heads is a solid budget option just about any Cam/Tune can snezze on in and make 500whp
The blue print heads are still 1200USD each so with to doorman intake and heads it's close to 3k just for the heads and intake. so its not the cheapest way to make 500hp when you can port the 706 and still get there. Is less time tho🤷♂️
@@mackenziehutchison4838 WOW i just price checked that there are lots of $600-900 LS3 options. scratch the blueprint. the GM part # 12675871 are $800 ish and RHS is under $700ea that's new pricing, if your local machine shop can beat that for a Tank/ flux/ lap & seat pressure check good for them mine can't.
a mild 6.0l with ls3 heads won't make 500 whp
@@richardholdener1727 mine on one dyno mild lq9 with ls3 topend made 414hp on one dyno. Was disappointed. Got it returned on another dyno but they refused to run it in 1:1 because I had 2.73 gears and base was 370 and retuned 395hp
Love your videos, and I've watched all your 6L videos(I think). I have a stock LQ9 in a denali. If I did 1 3/4 headers, 706 heads, what cam would you recommend for a daily driver/work truck, and how much power do you think that would add?
truck norris
@@richardholdener1727 by your estimation, how much power would this combo be over stock?
For street driving it’s all about the low end of the torque curve. The 706 heads have the smallest chamber and that’s the biggest reason they excel. The TFS 225s likewise have 65 cc chambers (ie, smaller, just not as small) and beat the rec port heads in part due to the increase in compression. I think the ports are more refined to take advantage of the 13.5° valve angle, too. They’re just better-but my engine came with 823s…I’ll stick with them for now.
your not wrong but if you look at the 799 Vs the 317 head, the ONLY difference is the combustion chamber volume....... you can easily throw more timing at a 317 head than you ever could on a 799 but this was a Head VS Head test. same goes for Rec Vs Cat port. you can fix the minimal low end losses with some timing and fuel. at the end of the day we are splitting hairs 8lbft here or 19hp there. I can get LS3 heads and intake attached to a running short block at Copart 2 or 3 times before I pay for the TFS 225's
Also worth noting, the expensive trickflow heads required an expensive FAST intake to make the HP/TQ gains. Whereas, Mr Holdener has proven the (cheap) truck rectangle port intake to be equal to the LS3 on (cheap) rectangle port heads
@@kylemilligan752 Yep. Got one of those, too.
I don’t understand why compression ratio is not talked about more. The 706 heads have tiny chambers. That’s why they work well in these applications. Same with all these cam swaps. Put these large cams in otherwise stock engines and the results aren’t nearly what they could be if the compression was straightened out.
chamber volumes were provided in the video and compression is not what provided the change in power offered by the 706 heads, and the cam run on this motor was run with a stock bottom end and stock heads!
I was dead set on 243’s for my lq4 but now I think I might go 706. But the non castech ones. They cracked on my original motor.
Once again, great video. Long story, short, 6.0 NA, port some 243/799 heads, optimize compression, let it eat.
The greatest expense is usually a stroker build. Using new parts hen ending custom balancing. And many time over boring the factory block. But with chinese turbos and e85 the game has changed.
Bloodviking
I have the mildly ported 823's in my LS2 with LS9 cam with a Turbonetics 78 mm with a 1.15 AR housing. What do you think about this combination for power?
ls9 cam is cheap-but suffers a lot down low-not a good match with the rec ports if you want boost response
Cam, headers and a e-bay turbo youll come out way ahead for the $ spent.
Richard what changed on the software to no longer show different colors per run?
I can only do that at westech-not with viewer on my computer
When running these combinations, changing heads, cams, intake ect, do I need a Holley hp system or dominator? Or can I use stock computer and turner. Or is it as simple as getting it dyno tuned? I want to know before pulling my 2002 Cadillac Escalade apart. Thanks!
Would the 317 head work well if you could keep the compression up by changing the piston?
they all work
@Richard Holdener come on tell me the secret combination. I know the 706 works well because the compression goes up and the downside to the 317 is the compression dropping. Would the 317 be any better than the 317 if the compression was the same my changing the piston?
@D BAIRD from what I can recall from other videos, the only problem with this is you can only mill so much and dome up so much as well until you start running into available valve clearance issues, lift on cams as well. So to me it seems like you are just money and time ahead going to the 799 of aftermarket heads. Instead of trying to figure out that magical combination of pistons, milling, cam specs, rocker ratio, pushrod length, and vavle train components.. just slapp on a set of 799's and half the problem of the 317's is fixed
The 317 head has a lazy slow combustion chamber and in my experience requires more timing to make peak power vs the 243/799 head.
@Mason Campos with a compression calculator the compression comes to 10:5 :1 without modifying the head with a 5cc flat top because of the compression height of dss piston. I was wondering if that would be and better than the 706 with a dished piston?
I'd like to see mill 799 heads vs bigger valves 706 heads
In my opinion, there is no wrong way to build your own build. Until someone pays for my upgrades ill build it the way i want it. You should to
Richard still out here doing the work everyone wants to see
Nice. So would you go rec port with adding boost for the extra flow?
depends on power level and application. but likely not
This has been proven time and again by Richard and on Engine Masters, whatever your combination produces NA, boost will only amplify it.
Build the engine for your purpose. If you want to throw a turbo on your street car, you don't need rec port heads. If you are throwing a turbo on a "race" engine, turning high RPM, rec port may be the way to go.
Weight saving an low end torque is what i see as benifical in a truck.
Amazing info ❤
The na limit of stock heads change when you boost the engine.
I remember some of these comparisons from other tests you've done. I'm sort of convinced now that it must be the camshaft that makes my current combination such a dud.
If only I had unlimited dyno time and wasn't daily driving my truck...
I would absolutely swap in a different cam and give the 862s another chance.
As Rich would say: Wrong Cam
What’s your set up? Do you have a high/low stall torque converter? It could be something else.
@@daviddenman7479 It doesn't make much power. Even Richard has said something seems off. I've offered to share my tune file with anyone that wants to have a look. It's an LQ4, 862s, TSP CHOPacabra cam, TBSS intake, 92mm TB, headers, exhaust, CAI...has all the supporting mods. Tuned on 93 octane, etc. It made 336HP/336TQ 4L80E, 3000 stall. My old cam and 317s made 327/369 on 87 octane.
I think my next place to start chasing things is a compression and leak down test. If that checks out good, it's time to blame the cam as being a poor choice for this application.
@BlueCollar Hotrods I'm just curious have you checked pushrod length? Don't think it should be an issue with that cam, but different heads on different motor sometimes can throw things off.. just my opinion, I really feel 862's are a restrictor for 6.0L. But even so it seems like you'd have to have multiple misfiring cylinders to have those numbers.. good luck figuring it out
@@masoncampos7043 I didn't. Block and heads are untouched, I threw in a set of stock pushrods. The valvetrain isn't noisy, etc. Aside from the weak power numbers, it runs good and is reliable.
Compression helps low rpm power 99% of the time . A small chamber 5.3 head can get you in trouble on pump 93 a lot quicker than the larger chamber head too, on a big bore ls. Its trade offs , but its important to make people understand the real world consequences of the switch .
I hear people dogging 317 heads all the time , saying they won't make power . Its true that they suck on the wrong app , just like every single other thing that uses physics to function . A 71cc chamber on a small bore engine will be lazy , just like a tiny chamber headoin a big bore with make great power but be knock sensitive on pump gas.
Hey Richard,
Sorry for responding to an old video.
I have an Lq4 I’m prepping for a build.
I found a set of 862 heads for $80 so I’m leaning towards swapping the 317 heads for those.
This engine is going in an e46 bmw for a drift build.
Would the truck Norris cam kit be a sufficient option for my application for should I be looking towards a bigger cam like a SS2 or SS3?
Thank you for your help as always
depends on the rpm you want to make power at
@ 6300 rpm to 7000
Yes 799 heads can be found on 4.8L from 2008
Hi Richard hope all is well
Im into rebuilding a 383 stroker using 5.3 block just revisited this the 5.3 engine has 706 from your video on 5.3 stroker build you use ls6 heads .
My project is torque from researching your test the 706s have good low end torque witch is my goal
Your thoughts please
Cheers
Aaron
New Zealand
Need to do the trick flow heads and a 799 cnc port and see the difference
see the big head test video
I've seen people spent crazy money on good heads on boosted engines just to make a lousey 30 to 40 hp. Budgeting is wise. 4k for a set of heads that add 70 hp is not great when you could add twin turbos for 400 dollars and get 200 to 400 hp from boost alone.
I always thought cathedral port heads were factor great from the start they had to make out the gen1 smallblock so there you have wonderful content and it would be nice to do it with 4150 style intakes and holley or atomic efi.
I have run single pane intakes many times
Well i will search you content sorry
I think that was because back in the day EFI was VooDoo/ witchcraft and guys where clawing at carb options and even distributor options. as the tech has advanced and EFI has become less of a dark art.
Terminator x has lowered the efi barrier of entry to be cheaper than a carb for the LS.
Also, search out Joe Simpson and you’ll find dozens of tuning videos to make it very easy to do it yourself.
im in need of help. i have a 04 ls swapped 5.3, in a 88 cutlass. the car ran great for about two months, then one day it just shut off,, after checking the system[wire harness] i found that the two power wires that hooks to the starter and the crankshaft sensor wire had burnt into the header, so i bought a new stand alone wiring harness, once i finish installing the harness, the car started up but it had a really bad vibration so i shut the car off and rechecked behind myself to make sure everything was in its place as it should be, which it was so i restarted the car [still had a bad vibration] but it ran for 3 mins then shut off, in would not start again. so i went to checking the possiblities , i check fuel in which its getting 59 psi of fuel. i check all my grounds , they all had good connection, i check to see if the ignition was getting 12v and constant 12v which it was, i check to see was the the coils getting ground and 12v which they both was but i wasnt getting any sparks, so i check the crank and cam sensor with they was both getting power so i replace them just in case and still no sparks.. can anyone please point me in the right direction. on how to fix this..
do all the cylinders get spark and fuel?
@richardholdener1727 they all getting fuel but no sparks
Do a cam test on gwatneys cams
Great info
I want to see a LS3 head on the Trophy 4 cylinder. Or any LS head.
What do you think about the TFS 225 heads vs a rec port on a 408 stroker? Seems like this TFS 225 head is a solid choice. I'll be running upto maybe 7200-7300 rpm max and an occasional 200 shot. Seems like the tfs 225 and fast LSXR 102 with the right cam could be what I go with. Thoughts?
DONT KNOW WHAT YOU MEAN BY THOUGHTS
@@richardholdener1727 do you think a 408 would have more consistent power throughout the 3800-7300 rpm range with the TFS 225 and fast lsxr or would it benefit more from a rec port head and intake setup?
vs which rec ports?
@@richardholdener1727 yes sir that's correct
Hey Richard, have you ever dealt with milled heads (might have missed those vids). a good topic may be how much can you mill from a cyl head before needing a different length pushrods. im stuck in that dilemma now. i want to mill the stock 823 heads (bought it used from junkyard) but already have sloppy stage 2.
depends on how much lifter preload you currently have
@@richardholdener1727gotcha. Im not even trying to mill for conpression moreso the fact that im buying used heads so to make sure its flat maybe even mill .005 but idk how much that affects the stock pushrod length.
But would also be a decent topic to explain how to check all that out.
.005 changes nothing on pushrod choice-and milling the head a given amount changes the pushrod length requirement by that amount. But since you have more than .030 (for example) of adjustability of standard travel lifters, there is often no need to change pushrods.
Does the VVT on the L96 (and its rec port heads) make up for the low end torque deficit perhaps? Since the L96 was the last hurrah of the LS engines in the HD trucks you'd think they would put their best combination together. I think the stock 360 hp rating on the L96 is very conservative.
Trucks have crap intake and exhaust. A L86 has the same; heads, cam, compression as a LT1. The difference is intake and exhaust manifolds, intake air ducting, exhaust system and tune. Thats it. There is a 35 or 40hp difference between a L86 and Lt1.
The L99, the 6.2l VVT from Camaro SS with auto has 400hp. That's 40hp up on the L96. That 360hp rating is probably a little conservative but I doubt more than 10hp.
The trucks, especially the 2500/3500 have a really restrictive intake and exhaust system that keeps things quiet.
Even the L8T has the same heads and cam as the LT1 and a little less compression. The manifolds, ducting and exhaust drags that down to 401hp...
So an intake and exhaust is a 40 hp promise?
The ly6/l96 are a full point less compression than the l99/ls3
I haven't look through every comment but can I still use the 706's if I use the cheap 87 octane on a daily driver and still get all those benefits of the higher compression. Does that change things at all being 87 is much cheaper than premium. I'm talking daily driver and a which one would be best when cost to drive is considered.
not if you have to pull timing when you run cheap gas
Are the head gaskets go bad often I have a 5.3 with 706 heads put in my swap and I have a leak in the head getting head gases in my cooling system should I just change gaskets are heads also it has 706 cathedral heads came out of 2004 Chevy Tahoe I believe ! What is best head gaskets to use on the 4 kid show string budget !!!
stock head gaskets should not leak-it is not the gasket-figure out what went wrong first.
So, again, the Coyote wins in every aspect. Great video Richard. 😃
Smoke mote crack
So use the 799 with more displacement or boost. Got it.
neither of those
I have a question you might can answer if you see this… I have a stock ls2 so flat top pistons currently running 799 heads but they are worn out and I have some stock 706 heads that I would like to do a quick swap with.. but my concern is compression!! I’m on a 93 tune and would like to stay on that being my daily vehicle. Will this be okay?? From what I read it’ll be 12:1 static CR which I’ve been told is insane.. but want to know your opinion! And if you have anything else you feel like I should know please tell me
IT WON'T BE 12:1-IT WIL ONLY CHANGE BY 3-4/1OTHS
So basically tfs 225 would be a great upgrade to a 5th gen ss with a cam
Hey Richard I have a lq9 I'm getting refreshed and I just picked up some non-cashtech 706 heads what cam, pushrods, springs and what head gasket do I need to put it together
what power level?
@@richardholdener1727 looking for 450+ hp and tq I like what I saw in your video I would copy it exactly if I knew all the specs
Got a 2000 c5 vette, 6speed LS1 5.7. The heads on the motor are 241, I’m planning on swapping them out for 706 heads that I got from a 5.3. I’ve seen your test and notice how the 706 heads outperformed all the other heads. My question is, do I need to do anything to the heads to make them fit on the LS1? I’m planning to go mid to high power close to 500HP so are the 706 a good choice?
you need ported heads for 500 hp
When are you going to do a big bang nitrous motor again should use a 6.0 and let it eat
I wonder how the 225 ported head with ls3 intake manifold would compare to the fast intake manifold
225 TFS heads are cath port and don't work with the LS3 intake (adapters are a terrible idea)
@richardholdener1727 ohk I didn't even think of that
So would milling the 799 heads make up for the down low loss?
It should. Perhaps not all the way when it comes to off idle but by 2k+ it should
Dou ypu know any potent v8 you can buy in Europe for cheap?
Correct me if I'm wrong but I thought the 706 vs 799's on the cathedral video did the opposite on the 5.3. With the 706 making more peak, and 799 low end power?
nope
The 706 made equal to or more power everywhere than the 799 on that 5.3 test
@splitface454 yeah I just rewatched the short version of that. I'm guessing the small bump in compression is not as beneficial as the flow of the 799 on the larger c.i. motor. Wich is why I choose them for my 6L
I have a 6.0 out of a 02 escalade going into a c10. going with a truck Norris cam. My question is my engine has 317s on it is it worth the upgrade to get 799s if I’m just replacing stock with stock no work other than springs and seals?
799s would make more power than 317s
What I wanna know is do you think the 706 heads would gain much torque on a stock 6.0 you know for helping out a big heavy Denali XL, I know this test probably has never been done I’m just wondering if I could still run on 89 octane or less
My dad has 799s on his 6.0 with a stage 1 BTR towing cam. It’s a torque monster! He drags logs out of the woods for his sawmill with it. It’s a crew cab 4x4. The thing sounds crazy under load with a big tree dragging behind it 😂
@@chandlerlofton6536 yeah definitely better than the 317’s
a 706 head swap on a 6.0l to replace the 317s is a sizeable chunk of power
@@richardholdener1727 thank you, I’m only interested in power off idle to 5000 RPM or so, what kind of fuel do you think I’m gonna have to run if I do the swap ?
@@DSRE535 dad runs 93 in his, but I think 89 would work if it’s tuned for it. I think the compression came out to 10.1 or something like that.
Stock lq4 and untouched 706 heads, what head gaskets yall using? What thickness?
.053..could also use .041
Hey Richard could you do a review on the 862 heads?
i have many times-same as 706 heads
@@richardholdener1727 Ok thanks
Rich whats the best head to use on a 5.3 ls in your opinion?
the best stock head is shown in the video-for after market, the TFS 205 works well
@@richardholdener1727 Thanks Mr. Holdener. I'm going back and looking at all the videos on the LS and getting all the info I can on them especially the 5.3. I'm a Johnny come lately on the LS. Thanks for the vids and the info.
Hey rich, I’m I turned to start a 408 stroked. Btr 233/248 what heads should I go with n/a? I think I heard you saw if plan on running boost I should keep my 317s but can’t get why?
Say*
HOW MUCH POWER DO YOU WANT
@@richardholdener1727 600+hp I saw one that you had used afr 245 heads but didn’t work right for that combo. Would it still be a good idea to run them for future boost?
Need to finish the gen 4 6.0 big bang
Is the torque specs stay the same when you add head studs? Thank you.
no-torque specs are specific to the fastener
when you speak about stock heads valves spring pocket is oversized for huges dual springs correct?
NO-NO NEED TO CHANGE SPRING POCKET FOR EITHER BEEHIVE OR DUAL SPRINGS
Richard, have you done any high rpm solid roller testing on these engine combinations? If so I've missed it.
no sir-no solids on an ls
Quality air flow, both velocity and average flow, always make more power.