HOW TO MAKE 500+ HP WITH STOCK 706 HEADS. 706 VS 799 VS LY6 VS TFS HEAD TEST! 514 HP WITH 232 CFM! 

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!

Always amazes me how good the "bad" LS heads are.

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.

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!

Love your new formatting...shortening the video but putting a concise and large amount of info on the video. Thank you!

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.

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.

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.

And this video is why you’re my favorite RU-vidr!!!

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.

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

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.

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!

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!

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.

706 over 799s for me as it may help spool rate. Then you can make up the few hp up top but adding boost.

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

6 liter with 706 heads and a Truck Norris cam should move things fairly easily. Those heads are badass for towing purposes. 😊

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.

just plain ole good tech to have info about, thanks Richard!

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.

SBC and BBC , LS the most used engines in all forms of racing, dependable,cost effective, horsepower.

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.

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

Damn, I expected more than a peaky 10hp gain from the 799’s. I bet they’ll do better being milled for compression tho.

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💪😎

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

I like the low end torque numbers from the 706's. Kind of what I expected with the higher intake velocity they offer.

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!!

Gawd I love this channel !!!! 🎉🤘🏼😛

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.

Good test that many struggle with.

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.

I'd like to see mill 799 heads vs bigger valves 706 heads

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.

Need to do the trick flow heads and a 799 cnc port and see the difference

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.

Once again, great video. Long story, short, 6.0 NA, port some 243/799 heads, optimize compression, let it eat.

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

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 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.

Cam, headers and a e-bay turbo youll come out way ahead for the $ spent.

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.

Thank you for the heads line up Richard! Which One of these stock heads produced the highest peak torque on the 6L?

Weight saving an low end torque is what i see as benifical in a truck.

Amazing info ❤

Richard, love the content. Do 706 heads need any machining or special attention when going onto an LQ9 bottom end?

What head gaskets did you use with the 706 heads?

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

Yes 799 heads can be found on 4.8L from 2008

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 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

The na limit of stock heads change when you boost the engine.

Richard still out here doing the work everyone wants to see

Scrapped my old H/C/I combo after watching this for my IROC. 4L80E plus what converter and 3.73 rear? Will see full street & occasional strip time. Anyone? 🏁🇺🇸

Would the 317 head work well if you could keep the compression up by changing the piston?

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 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.

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?

I bet the trick flow has a MUCH better valve job.

So, again, the Coyote wins in every aspect. Great video Richard. 😃

Great info

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

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 what changed on the software to no longer show different colors per run?

I want to see a LS3 head on the Trophy 4 cylinder. Or any LS head.

So basically tfs 225 would be a great upgrade to a 5th gen ss with a cam

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.

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?

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.

When are you going to do a big bang nitrous motor again should use a 6.0 and let it eat

Funny how people don't bash Richard's article's/results on forums anymore since his channel was created 😂

Nice. So would you go rec port with adding boost for the extra flow?

Its almost too close to call between 799 and LS3 head. The LS3 intake could easily make up that 20hp difference.

Give me the 20hp, on the drag strip I may need that hp more in a bracket race.

Do a cam test on gwatneys cams

Need to finish the gen 4 6.0 big bang

I wonder how the 225 ported head with ls3 intake manifold would compare to the fast intake manifold

Need to do a video of 862

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.

when you speak about stock heads valves spring pocket is oversized for huges dual springs correct?

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?

So would milling the 799 heads make up for the down low loss?

Why not run that Fast intake on the other cathedral heads??

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

Just don't over cam your rec port if you want a street torquer. Same as you don't over cam a 4 valve.

Quality air flow, both velocity and average flow, always make more power.

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 need to borrow a cam I’m on a budget lol

Wish there was more info on the 862 heads. I picked up a rebuilt set for $200. Hoping to go on my fresh lq4

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?

I have the 706 heads, my question is will I be able to put my stage 3 Texas. 550 cam in the engine without changing the springs out? Without damaging the heads?

Hey Richard could you do a review on the 862 heads?

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?

PRC 225 as cast for my OG LS1 or stay with my decked 706's? Dropped them by 25 thou. I think I calculated a 57.5cc combustion chamber with that change

Stock lq4 and untouched 706 heads, what head gaskets yall using? What thickness?

The 4.8 in my 08 gmc has 799's

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