BOOST VS HEAD FLOW-WHAT STOCK HEAD SHOULD YOU PICK FOR A TURBO LS? 706 VS 317-DOES MORE FLOW MATTER?

[@supercoupe28]

I love these statement/ questions! Personally, I think the only bonus to the 317 head is the possibility of running a bigger boost number on pump gas before the fuel becomes a problem.

[@senseimarvin454]

Run the test on 91 or 93 octane and run the boost/timing up to the octane limit. On race gas its pretty clear the 706 will win hands down, but on the street running pump gas i think the extra volume of air/fuel charge (same as more cubic inches) will probably show a big enough change to give the 317 the advantage. the problem with most dyno data is that the testing us usually done on race gas, E85, or straight alcohol. Most people run pump gas powered hot rods, and mostly on the street. I know I cant afford to drive around on the street burning C16, and E85 is nearly impossible to find where I live, and i suspect I'm not the only one. Anyhow, i just think the fuel type needs to be a much bigger part of the test criteria, rather than a minor mention at the end.

[@francisbeaudry8598]

no race fuel in wich place do you living sir

[@senseimarvin454]

@@francisbeaudry8598 We have race gas, Oregon isnt the moon, but last time I looked at a 5 gallon can of C16 it was well over a hundred bucks. Thats fine for a track car, but for most people thats not going to be something you can run on the street without a really fat wallet. For the drag-n-drive project Im building Im running an EFI dual fuel system with pump gas in the main tank and e85 in a small tank on a second set of injectors that switch over at around 90kpa. and i think a lot of drag-n-drive people are starting to do something similar. E85 prices aren't too bad for street driving, but ironically the availability of this "eco-friendly" fuel here in the land of rainbow haired greenie's is very hard to find. especially if you are away from home and need to find a station nearby. But anyhow, this is going off the rails, my comment was about testing the heads on pump gas instead of race gas. And while im at it, maybe test it on a turbo'd 6.0, since thats the engine 317's came on anyhow. I think it comes down to the balance of peak cylinder pressure and Volume of air/fuel charge, vs combustion chamber shape difference. when you hit the wall on octane with 317's you'll have a higher volume of air/fuel to push that piston down, but will that advantage overcome the less powerfull combustion chamber shape? testing both heads on race gas and the same boost pressures does not answer that question.

[@francisbeaudry8598]

@@senseimarvin454 tank for feed back here in quebec 210 /250 $ for C16 BUT WE HAVE 3OR 4 PLACE TO CHOOSE

[@bcbloc02]

Need to move to the midwest we have e85 at the majority of stations and its like .50c/gallon cheaper than 87 octane

[@kevinwest3689]

You read my mind. If I run my 799's it will be 11.1 if I run my 317's it will be 10.2 if I halve to run 91/93 even with 180° 200° CT Quinch at .0.040 Average Air intake temps. You have to be right on the Ragged edge with the tune with it 11.1 Nothing like driving around puckered. Or 317's about 10lbs on 91 Have joe simpson tune it to the Neighborhood of 650whp 🤘

[@randallmason9687]

Just put a 317 on one side, and 706 on the other side! Send it!!

[@nessie42786]

Like a dual plane intake manifold. 😂

[@The980Junior]

It would run and drive and 90% of people wouldn’t know

[@stuartwall8212]

best of both worlds. 😆

[@raymondgoshorn2005]

Hi Richard, I think the more interesting question is what is the better head if all u use is pump gas? Remember the reason the compression was lowered on that BBC 540 (8-71 blower I think?), from a few years back down to 8.5 to 1 was because it was a "street rod". I don't think u can really push the "317 heads" to really gain from going up in boost to catch up on the "706" heads as there is insufficient difference on port flow. If you really go with the "pure street" angle, then you would see the 317 heads able to do something that the 706 cannot; live with boost and compression w/o the E85, methanol or race fuel's. Just a thought.....

[@bobqzzi]

Theoretically, the lower compression heads with better airflow will allow more boost on pump gas before detonation. However, that's theoretical and would need to be tested empirically.

[@boost1728]

It’s been tested 20 dozen times and you’re absolutely correct… sometimes. When runbibg E85 not so much- but 87 octane, yes definitely. The reason Richard can’t prove this is because he doesn’t have a way to run knock sensors on the dyno so he runs the same timing on all similar setups rather than pushing each combination to its limit. This is also why he doesn’t see make additional power with water meth or E85- the engines are not tuned properly for those fuel sources. Any tuner dialing in an engine that utilizes knock sensors knows the truth that Richard doesn’t but hopefully one day does. The only time what you said doesn’t apply is on good fuel that can handle the higher compression. That combination will make more power and still not detonate.

[@thefinalroman]

@@boost1728 706 heads have more deshrouding of the valves. That's why they make more power.

[@boost1728]

@@thefinalroman that is absolutely not why they make more power.

[@sstevocamaro]

Whatever comes with the engine lol.

[@joseiracheta3817]

So why not run the boost up to just under detonation and back off a little bit. The lower compression of 317 should allow more boost and maybe more power

[@crash5811]

Then the question is, does it have more potential for power on any given fuel? Or does it just handle more boost pressure?

[@falfighter]

@@crash5811 well we know the 317 can flow more but has less compression. with that said the 317 has more potential because you can run more boost and or timing.

[@boost1728]

This is common sense but Richard refuses to test this way

[@Mastermindyoung14]

Because you'll arrive at the same power level with less boost because of the bump in compression.

[@joseiracheta3817]

@@Mastermindyoung14 I would love to see it.

[@HeyLiana1]

I like the quick spool up of the 706 heads, but I like the high rpm flow of the 317 heads

[@lutherjackson_]

Don't worry, Richard. I listened. I have a built 6.0L with 317 heads, and I plan on adding twin turbos. Thanks

[@richardholdener1727]

points for listening

[@hayimthat1dude]

Waiting on the 3800 Big Bang video my dude

[@rocketsurgeon11]

Chamber design can affect power production. Facts... ;)

[@richardholdener1727]

points

[@nicklaw13]

As you talk of putting more air in. Let's see a stroker With 317 vs the 706 on a stroker application. Your moving more air. Air compressor right?

[@nemofoss9887]

Only way to test is same Boost say 20psi , add timing until mbt mbhp are acheived. If the 317 doesn’t handle more timing than the 706. Then the chamber shape regardless of cc is the determination. Or port and modify the 706 for the same flow and then flow is out of the formula. Bore shrouding , real world flow might be an issue also. Back in the old days we would offset head dowels to make more power on a max effort head because 315cfm did not make more power than 292cfm. But shifting the head .040” made hp more on both heads.

[@StationroadRatrods]

If you wanted to compare 317 heads to 706 then I’d want them to be stock for stock. By throwing out the “stock” rules you could also deck the 317 until the chamber CC was the same as 706 and it would also be an irrelevant test

[@RobbysHobbies93]

All comes down to the combination

[@bcbloc02]

I love how you say 7, 8 9, 1000hp is a good reasonable power level. I haven't found very many drivetrains that like that power level for very long. lol

[@richardholdener1727]

the drive train is the most expensive part

[@akassasin5768]

Bcbloc02 when was the last time you heard him say that 1000hp is great for the rest of the drive train?

[@chipcurrey653]

I think an easy answer is to spend slightly/no more up front on an 08+ 6.0 with the square port heads, which is like getting a 99-07 6.0 with aftermarket heads and intake from the factory. Then this conversation becomes more academic.

[@umakemerandy3669]

4:30 no, the point was when using pump 91 fuel the lower compression ratio allowing more boost making more power. I dont think the statement had much to do with flow difference 10:23 again, no, he probably is talking about the 317 working better when fuel octane limited and reaching for peak power

[@richardholdener1727]

he specifically said the greater flow in the 317-his statement wasn't about octane limited situations

[@umakemerandy3669]

@@richardholdener1727 hmmmm, i see. Shucks man next time include a screenshot cut of the comment on screen.

[@akmjolnir-v4r]

Liked, commented, and subscribed!

[@TheOriginalRedZMonte]

Luckily both of my motors came with the best factory cathedral port heads… 243 Mafia represent! 😂

[@kylemilligan752]

Back in my dynojet honda tuning days, a 11:1CR rsx type-s with greddy turbo kit 6psi would make 260whp. On 93 octane, ignition timing was down around 10-12 degrees to avoid spark knock. Hondata had very good knock detection. Exhaust gas temps were approaching the surface of the sun, but the combination was safe to beat on non-stop. Had stainless downpipes cracking and breaking tho. Had one rsxs customer bring good rods and 9:1 pistons to install. Made the same 6psi, same 93 octane, same hp/tq curves, with 6-8 degrees more ignition timing. Was no longer knock limited, and the egt gauge was no longer pegged. 61cc 706 vs 70cc 317? I will assume any gains from lowering the compression will stem from being spark knock limited on a particular fuel. Your results may vary.

[@richardholdener1727]

the above comment is a timing test

[@francisbeaudry8598]

@@richardholdener1727 timing / gaz octane= boost

[@kylemilligan752]

@@richardholdener1727 it was very much a timing test. However I learned much from a knock limited 11:1 k20 to a 9:1 k20 on the same 93 octane fuel. My dynojet graphs overlaid because the 9:1 would take more timing. When you get into pump gas compression ratio vs boost, you should spend some time on knock detection that really works

[@CrazedPerformanceRepair]

Would the 317 make more power under boost due to the lack of combustion efficiency and larger volume with a low grade fuel perhaps? Not a flow related power gain but more so the possibility more boost could be run before detonation occurs?

[@richardholdener1727]

lower compression could work with low octane

[@chris-mts]

i would like to know what the difference is on pump gas. Can you use more boost and ignition timing on the 316 heads? As a daily driver.

[@ajjskins]

Honestly, it really doesn’t matter whether it’s a 706 or 949 head if it can flow a certain amount of grams per second you’re going to end up with a certain given amount of air and that can be combined with a very certain amount of fuel and you’ll get a very certain amount of combustion. All things considered if the smaller head can only push for example 109 g of air but the slightly bigger head can flow 118 g of air if they’re at the same level the one that has more grams per air will make that much more power. It kind of goes back to the old saying there’s no replacement for displacement and a turbo charger or head design just displaces more air. That’s a fact. This is why some of the four-cylinder engines run in 25 pounds of boost are able to make the same horsepower as a V8 with only six or 7 pounds of boost.

[@BriansLastname]

Logically, I think the only way to utilize the extra flow is with more cubic inch. 6L and stroker crank would naturally demand the additional flow.

[@joeyjojojr.shabadoo915]

I have a great idea for heads for your upcoming 4" bore 4.8L that you mentioned...... I would love to see a set of 706/862 heads with both intake and exhaust valves completely UNSHROUDED in the chamber with a bit (alot) of grinding work to see if they can maintain their crazy low end response and then still have the flow to feed up high in the RPM range.

[@jasonm3109]

I would think that back pressure will be a problem before the air flow could make a difference, and there's no way you're going to hold a headgasket to get to that point anyways.

[@smithfamilyvegetables7666]

The 317 head came on a high output 6.0L truck motor with flat top pistons the LQ9 LS motor. A 5.3 came with negative 10 cc dish pistons. The LQ9 with 317 and flat top pistons had 10.5 to 1 compression. I have 317s on a NA LQ9 with long tubes, fuel injection 3/4 race lumpy cam and 350 gears. It just seems to rip the tires off on my vehicle.

[@swamie100]

the 317 head would make better power if the fuel was the factor which is a lot of the time 87 octane you could run significant more timing with the 317 and more boost. With perfect conditions the compression is hard to overcome. The 317 is a more forgiving boost head

[@ThePblawler]

I really would like to see the test where the two were tuned to detonation with timing and boost to see which one makes more power. Of course within the timing and boost limits if the 706 it wins on a 4.8 or 5.3

[@BearFulmer]

Read every comment best i could. I would want to see the heads on an engine with equal compression. Not sure of bore size, cubes should be as equal as well. Tough test. Unicorn test

[@BraapZ]

👍great question, I wonder if a super-whiz-bang aggressive camshaft might help offset this, to recover some of the benefits of the greater flow 317 vs the better chamber 706?

[@richardholdener1727]

they do the same thing with a different cam-they both gain power

[@Gregoman89]

Well yeah adding more atmospheric pressure you just add corresponding power since a motor is just an air pump. The real question is will you get less detonation with reduced compression and better cfm? Meaning can I run more boost on the 317 prior to detonation and will I get less of a diminished return at higher levels of boost?

[@seanbragg1696]

It really comes down to valve seat diameter on 317 vs 706 I believe milling is less of a power adder

[@jacobvanhalteren7452]

The 317 has lower compression so under boost I assume it would reduce pinging and allow more timing at the same boost level. So wouldn't that make it possible to get the power back? Would that only be better assuming fuel is the limiting factor?

[@danhall5218]

Definitely maybe

[@bobbywalter5320]

sometimes.

[@mikesilk6518]

Seems like a displacement problem, but really you need to think why does the higher flow make less power, there's plenty of reasons it could, once you figure that out then you can decide if any change to the rest of the engine will fix it. A bad combustion chamber will effect flow and overall engine power very differently for example, if it's that this combo might work better with a bigger bore, maybe on a ls7 they'd out perform

[@killfoot961]

Well good to know my 706 heads are truly worth keeping and better than the 317's. Dyno sheet dont lie. All in all, its part of the chamber of secrets.

[@thatracinglife]

My guess would be the only way the 317's beat them is in an octane limited scenario. For instance, Alaska only has 90 octane as their highest grade of fuel. Also maybe if you're on the max end of a smaller turbo when heat becomes an issue. Would be cool to compare them in that situation.

[@wheelbasemedia5814]

I would submit that Alaska has a cooling advantage over, well, anywhere south of there.

[@thatracinglife]

@@wheelbasemedia5814 it can be 90s in certain areas in the summer up there. Not always THAT cold.

[@pressurevessel8504]

Fenton black widow manifolds. Would be a cool sb dyno

[@seanbragg1696]

If your doing that test might aswell combine water cooled vs air to air test in conjunction with the heads

[@richardholdener1727]

that video is up

[@shockwavemi1]

Richard, Love the videos but i cant help but wonder why they all center around making power @ 4500 rpm + when in reality very few people can drive that way. Can you make a video that shows guys who want all low end power/torque I.E. Jeep guys and light to light racers? You know, guys who cant really get to a track but still love to be set back in the seat even if only for a moment.

[@C5Z06CarGuy]

Richard said yall's babies is ugly... FACTS!

[@ThePblawler]

Lets see on pump gas where the boost timing and power limits are on both

[@richardholdener1727]

I think he covered that in the video

[@derekwerner1019]

Are you running the same timing with both heads? You can run more timing with the 317.

[@englandtra]

Could you do a fuel test for example tune pump gas kind of rich maybe 11.0-10.5 then see what percent of methanol you could add to your fuel to get the air fuel back to a more typical ratio then see if it picked up power

[@C5Z06CarGuy]

Higher static compression doesn't always make more power with forced induction. There's a crossover point at which higher static compression starts losing out to lower static compression supplemented with forced induction. For most engines, it's around 20lbs of boost, lowering static compression to allow for more boost will actually net more power, even if the effective compression is equal. higher static compression can't add oxygen to the combustion even, it can only squeeze what's there, it lowers volumetric efficiency but raises thermal efficiency. A turbo can do both. It would be interesting for you to test this with the same set of head, where it starts with a thicker head gasket, then a thinner head gasket, and then get's milled down, and test each phase with 10psi and 25psi.

[@richardholdener1727]

higher static compression added power way past 20 psi-look at class racing where they regulate turbo sizing (higher compression adds power)

[@C5Z06CarGuy]

@@richardholdener1727 It depends on the engine at what point the crossover exists, but it does exist. It's probably higher for something like an LS that has lower starting volumetric efficiency compared to a Ford Coyote or a Honda F20C. Just think of it in the terms of volumetric efficiency only. What is going to end up with a higher VE, a high compression motor with low boost, or a low compression motor with high boost? High boost. You're increasing the swept and or unswept volume so it can be filled by the turbo. An engine is an air pump right? A larger volume of air means more power potential. Yes a high compression motor can make power with boost obviously, and there's plenty of advantages to that. But if we're strictly talking about maximum power potential, lower compression has the greatest potential. But enough boost has to be thrown at it to raise the VE to that point. Test it if you don't believe me. Or go talk to a mechanical engineering professor. It's not my opinion, it's physics.

[@akassasin5768]

I think you are missing the point. It's not the engine it's many other factors. Especially fuel amd temp. Which you left out. It's not "jUsT PhYsICs" when you leave out a bunch of "ThE pHySiCs"

[@C5Z06CarGuy]

@@akassasin5768 You're not making a point. So there's nothing to miss. If you change IAT and fuel, it's going to effect both scenarios. Either scenario, lower compression with more boost makes more power. It's not a debate bud.

[@akassasin5768]

You're still missing the point "bud" of course the highest compression isn't the best in all cases ever. No one said that. It's a trade off just like everything else. It's not our fault that you're to stupid to understand that with better chambers and fuel 17:1 is a reasonable compression ratio for high boost. If you can't comprehend this I would recommend actually doing your research next time before debating about dumb shit that no one even implied.

[@jorgefive0]

Every head is a turbo head 😉

[@vne5195]

But with 87 Octane fuel... FAX~

[@richardholdener1727]

exactly

[@RobbysHobbies93]

If I'm just bolting factory heads on I'm going to lean towards compression

[@philthelawnman]

I've made some good not massive power from old school sb chevrolet and 455 buick and Pontiac of wich I only bolted together the 455 s as each were bought by someone that lost the vehicle. However I only know what little I do from your channel, Travis Black I think is his name and power Nation. I have avoided these super heavy small blocks like the plague until last year. But what I want to know is what head is equal to the Iron Angel plug heads on chevy 302 and the 400. May not have been factory on the 400 I found them on. But my Goodness it was a beast till a conecting rod crashed the cam.

[@juggernautdriveSS]

I am currently running a twin turbo build on a built bottom end LQ9 bored and stroked to 408 with CNC ported 317 heads. I would be curious to see how a set of equally ported 706 heads do under 25 30 plus psi of boost.

[@danielsullivan9865]

That’s the test that I want to see also. I believe the 317 heads with 2.05 valves or 2.08 valves will edge out the 706 heads. Need to test on an engine with large bore solid lifter, cam, high rpm, and big boost.

[@juggernautdriveSS]

@@danielsullivan9865 I have the perfect engine for it lol running a summit stage 3 turbo cam.

[@richardholdener1727]

TEA ported 706 heads vs TEA ported 317 heads

[@juggernautdriveSS]

@@richardholdener1727 that would definitely be an interesting video to see!

[@blueridgemountainprepper2166]

Sounds like a simple answer to me, add more boost to the 317 heads than you do to 706. Then the answer is always yes 😂😂😂😂😂

[@englandtra]

The only way it will make a difference is when cylinder pressure is too much for the fuel you are using the 317 may let you run an extra pound of boost or a couple more degrees of timing … I’m going to guess that the hp might top out the same at that point

[@mythos000000025]

Hmm I'm interested to see how this plays out for me. I have a stroked l33 with the 799 heads, forged rotating assembly with a final compression ratio of a tad over 9.5:1. I know cam specs also play a big role in power and needed octane. It'll get boasted eventually, gonna start off driving the car N/A before i aim for 650+rwhp with less than 10lbs of boost(hopefully) i did have it gapped for over 15...just to be safe 😅. Should be fun either way, less than 2900lbs with ....probably more than 400whp...should be spicy even before i go to kill me mode

[@rustywater3219]

Just making sure you're aware of weingartner's cam challenge. Sounds like it's right up your alley, to at least see the results.

[@richardholdener1727]

it will be interesting-I suspect a lot of guys making the same power

[@Jermo8115]

It’s a compression limitation question, not air flow. Does the higher compression of the 706 limit the max boost compared to the 317

[@akassasin5768]

It's a very dynamic question. You have to take in to account quench and chamber design to really know the limits. Higher compression sometimes is better all around as long as the chamber is designed properly.

[@screwball191145]

...So... if the milled 317 still make less power than a 706...why do better flowing aftermarket heads make more power without making additional changes (other than those AM heads)? This feels like a dumb question to ask, and I'm not receiving a MacArthur Fellowship Grant any time soon but I'm also not bringing up the rear of the class either.

[@383GT]

If combining big cubes, big boost, pump gas, and an intake and cam suitable for high RPM, I'd run the 317s.

[@b00st_SS]

I have 317 heads on my Chevelle, so the obvious fact here is they make more power than 706’s after 10psi of boost!! FACTS… I wish that was so, but seems it’s not

[@richardholdener1727]

fax!

[@michaelstoker6710]

I would think the 706 heads with the small bore would be less shrouded and flow more than enough to feed the small motor the large bore may benefit from the higher flow some. Probably wouldn't make up the differences in the compression. I can see the bigger heads making more power under boost at the same boost level. Being boost is a measurement of restrictions the smaller head should hit the boost level and be flowing less cfm. But not sure if it would even come into play on a 5.3. As there's not a huge flow difference. If it was like 50 cfm less something like the 706 flow 275 and the 317 flow 325 and still Probably only noticed on a large bore.

[@b00st_SS]

How bout 706 heads vs Rec port heads ? Does compression gain beat air flow there? Rec ports have 70cc chambers

[@richardholdener1727]

That video is up-706 vs ly6 heads (rec ports made more up top-lost down low)

[@Lagrange1186]

What if we tried na with massive cubes? Like 450+ la short block with all the camshaft. You’d tax the heads pretty hard and maaaaaaaaaybe find out if the flow finally wins over the better chamber design? I’m still voting 706/862’s but it’s another one at to text

[@davidwickboldt712]

4.8 pistons in a 5.3 with 317 heads. Compression with more flow. 😁

[@richardholdener1727]

706 with the same piston wins

[@davidwickboldt712]

@@richardholdener1727 Ain't no replacement for compression! That could be a strange test. Higher compression 5.3 vs a lower compression 6.0. What's the better bang for the buck.

[@Jermo8115]

I think the question is can the 317 heads handle more boost than the 706 with all things equal and does that translate to more power? Like 706 maxed out at say 12psi vs 317 maxed out at 17psi

[@codyhenry3926]

Figure out how much air your engine is moving on the cam and at Peak RPM.. Correlate that with head flow capabilities.. Then add boost pressure accordingly

[@diegoalonso6094]

Hey Richard just a question would the ls7 452 head work on a lq4 bored to 4.070

[@diegoalonso6094]

The cam is a 54-495-11

[@richardholdener1727]

I have not tried that

[@Ffdmotorsports]

Don’t stress the head. Stress the fuel and tune.

[@nicholaslapan1590]

So, dumb question, the 317 flowing better, how does that affect the way the turbo spools? Could more exhaust flow cause a faster spool? More drivable in the low RPM range maybe?

[@richardholdener1727]

the motor makes less power NA with the 317s, so it spools a turbo worse

[@EL-gu1oy]

Will you do a LT big bang test

[@GrandPitoVic]

But, when the 706 heads max out because of compression, can the 317 head keep going cause of the lower compression and make a but more top end?? Just curious

[@brianramsey5452]

Maybe on a big cube big cam high rpm n/a build. Would it come to the point where the 706 would be a big enough restriction to hurt performance enough for the 317 to pass and then boost. Like a max effort 600+ na build then boosting it?

[@richardholdener1727]

The 317 heads won't support 600 na hp, nor would the 706 heads

[@spazzofficial8420]

Please do a video on a twin charged 5.3

[@mumfordsgarage3407]

At what lift were the 317’s better? Maybe its the camshaft thats holding back the hp and the 706 is more efficient at lower lift.

[@richardholdener1727]

600 lift cam-it's not the wrong cam

[@stormracer05]

Are there performances gains in installing large intake valve on the 706? Or is shrouding too much of an issue at that point. It's unrealistic but I'd like to see the 317 chambers welded and reshaped with the swirl ramp.

[@bobbywalter5320]

thats when you find out its quicker and easier to buy a 243.

[@devin7632]

Can we try a Test with a flat top piston 6.0 with 706/ 862 heads running pump gas

[@frankfrosolonejr7010]

Hell now I’ve got the wrong cam, the wrong heads and wrong wheel drive on the gxp lol

[@IamKuahn]

Good video

[@Justls1v8parts]

Hi Richard how and would the 706 heads work on 5.7. Thank-you Aaron

[@richardholdener1727]

better than the stock 241s

[@Stckit1]

Hey Rich, hope all is well. Was wondering if you had any LS intake manifolds for sale?

[@richardholdener1727]

no sir

[@freyja4954]

Was this taken from a stream I think I remember this discussion

[@richardholdener1727]

yep

[@freyja4954]

@richardholdener1727 good have not gon fully nuts yet.🤣

[@Z83t]

Hey Richard, I would like to know if you've ever cracked a 706 head under boost?. I've heard the 706 casting is weaker (and known to crack).. vs. other cathedral port heads.

[@richardholdener1727]

I have not

[@ryandoyle4344]

Could this cam profile be more optimized for 706 heads? Perhaps another profile could be better optimized for 317 heads? If so, utilizing the same engine, which H/C combo is top dog?

[@richardholdener1727]

#wrongcam

[@DuraSled]

I agree.

[@sevencorter]

I think they might beat a 706 if the bore and stroke were maxed out.

[@bradmcgrath358]

LOL at the people still arguing Compression and Flow in the comments, even though you were told in the video that chamber design matters, port size matters, You were told that even if you mill the 317 to match the chamber volume of the 706, the 706 still makes more power. But you're still arguing compression and flow.

[@shadjohnsen8143]

This comparison seems to take a 706 headed engine with its compression against a 317 headed engine with lower compression. What if you had a 317 headed engine with the SAME compression as a 706 headed engine and then tested that way?

[@richardholdener1727]

the heads don't provide the same compression. If you want to make the compression the same in a head comparison, let's then make the airflow the same.

[@shadjohnsen8143]

@@richardholdener1727 ok how about doing this same test on just 93 octane?

[@95Sn95]

317 head it seems to valves have less shrouding

[@codyhenry3926]

Displacement needs to match air flow

[@V8Lenny]

Every head is a turbo head !

[@abramfehr2940]

243 vs 706 heads? Which one has more compression or what are the differences?

[@richardholdener1727]

799 vs 706 vids are up

[@abramfehr2940]

@@richardholdener1727 did some quick research. Didn't know 243 and 799 were almost the same. I'll check out those videos

[@joeyjojojr.shabadoo915]

Please explain the L33 5.3L (Alum block 243 heads) vs the LM4 5.3L (Alum block, 706 heads). Better yet, The LC9 came out with both flat tops as well as 3cc dish, but both had 243 heads and the 243/799 head engines were always higher rated by GM.

[@johnsonbobo2376]

He has videos of all the different small block heads. The 706 wins because coefficient of discharge and shrouding of the bigger valves. The 706 heads have 1.89 valves. The 2.02 valves are worse at shrouding. That's why the 706 heads win

[@travisblack417]

The LC9 is flat top only, when you say 3cc dish you might be referring to the valve relief pistons for the VVT motors.

[@GrandPitoVic]

By the time you spend the money to get into the 4 digit levels to make the 317 win. Just buy some aftermarket heads and save some money

[@VincentCarlotto]

just asking because u say stay with the heads you have. e85 6.0(hopefully aluminum) or aluminum 5.3. hopefully i don’t break the aluminum blocks but shooting for 1500 hp single turbo. should i get ls3 ported heads?

[@dallynsr]

Richard, isn’t this the now classic myth that lower compression for boost makes somehow more power, um…er with pump gas? lol I’ve heard you say for years that low compression motors show gains from boost but high compression motors with boost do better. (Higher Hp/Ci) And still this argument lingers around. What my question that is still out there is if more top end torque makes higher Hp N/A before boost then why not dyno and rev test up to 9k or 9800, and why wouldn’t you build a motor to last up higher then if it makes more power N/A before boost would make it sky high? RPMs make winners.

[@RJ_OneK]

I always miss the lives so I just came to a comment section. But I am building a 5.3 and I plan to sell it I want to know what rebuild kit and cam do you recommend(the pistons were rusted and my dad accidentally busted one of them beating it out). I would also like to know how much I should sell it for as a Long Block.

[@richardholdener1727]

it is harder to sell a rebuilt LS long block since the junkyard is full of running LS motors for cheap

[@RJ_OneK]

@@richardholdener1727 That is true. Do you suggest installing it in a vehicle?

[@RobbysHobbies93]

So then how much hp would a fully ported and worked set of 706 heads handle compared to 317s fully ported?

[@richardholdener1727]

they would be very close to the same

[@wheelbasemedia5814]

Can the 317s outperform the 706 in an NA application? If they can't, they won't under boost.

[@joseiracheta3817]

@@wheelbasemedia5814 but you can add more boost and timing with a 317

[@stuartwall8212]

why would anyone, on a street driven car, ever want to trade more power all through the RPM range to gain a little at the top? Even if it were possible, I think it is counterproductive.

[@jeremymardlin5381]

Have you run a 6.0 with 317's and a Truck Norris cam?

[@timtaylor6147]

Larger engines 317 simple It was never on the smaller engines Also Larger chamber at any boost has potential for more power by sheer volume of ignitable juice

[@richardholdener1727]

no sir