Heads for 1000+ hp turbo

We're in the process of putting together a high hp turbo combination. It will either be a 383 with a PTE-88 (if Jose can hook us up with a PTK Gen 1 kit ;)), or a 355 with a PT-76 GTS. We're running into problems with the heads, though. At first, the AFR220 Competition heads looked attractive, but they have a 12 week wait :shock:. That leaves Edelbrock (nope), Trick Flow, and LT4. I'm leaning toward the Trick Flows because of the thicker deck/port walls and larger valves. But the LT4's have advantages also like probably better fitment.

Any thoughts on this?

Mike

canfield makes a nice lt1 head! :)

Mike, I know what you mean on the 12 week wait on the 220's comp. ported. I waited 14 weeks for mine.

I think the best thing to do might be to call around to the different vendors. I would imagine that someone has to have a set of the comp. ported AFR's in stock. Even if they aren't 220's, maybe 210's.

For a project of this magnitude I'd wait for the AFR's. These are the only "proven" alternative at anything near these hp level for an LT1 head.

Rich

Though people have made that kind of power on GM castings, I would run nothing other than AFR's just for the sake of reliability.

Even if you had to buy a lesser casting and have it ported to your requirements.

I remember seeing someone recently in the For Sale section selling a set of AFRs..

Here's the link, not sure if it's what you're looking for..

BTW: I have no affiliation, just trying to help you out :D

http://web.camaross.com/forums/showthread.php?t=352594&highlight=afr

--Sean

I'm with Rich and INTMD8....a wait on the AFR's would be better than trying to compensate with an inferior head IMO.

I guess my question was, if a TFS head were ported to say 290i/220e cfm, would it really be inferior.

Too bad they quit making the Canfields.

Mike

Are you dead set on using "LT" heads?

Um. . . sort of. I'm dead set on using an LTx intake manifold. I understand that SBC heads can be adapted by adding the coolant holes and changing up the manifold bolt pattern. Is this really practical?

I have the same question. I just decided to run two of the Precision GT4067s turbos on my 383 project. I may order the Trickflows in and have them worked by LE. To me, on a boosted vehicle, the size of the exhaust port is the biggest factor (a good ported can shape it well), and the 195cc intake TF heads have about the same size exhaust runner as the large (210-227) AFR heads.

Is this not correct thinking, or am I missing something here. My goal is 1000rwhp. I have heard that the casting quality of the TF head is much better than the AFR, with better cooling passages AND the thick deck also.

Mike, I spoke with Glenn today and told him about the wait on the AFR heads....BUT, my engine builder does have a set of 210CC competition ported LT4 bare heads sitting in the shop in Houston and I have a line of some other AFR's and Trickflows. Not sure how much they would be, but I can find out. As for the setup, to be honest with you I've become a firm believer of the 355 configuration that I'm building a 355 spare motor to replace my 383 till I decide what I'm going to do with a Dart block setup. My customers results are hard to argue with, so I'm am definitely going to build a serious 355 LT1 for now.

Jose

. . ., to be honest with you I've become a firm believer of the 355 configuration that I'm building a 355 spare motor to replace my 383 till I decide what I'm going to do with a Dart block setup. My customers results are hard to argue with, so I'm am definitely going to build a serious 355 LT1 for now.

Jose, I certainly appreciate your help and input on the combo.

Your customers' results certain prove what you're saying, but I'm still having a hard time getting it through my skull that less cubic inches doesn't hurt a turbo motor.

Um. . . sort of. I'm dead set on using an LTx intake manifold. I understand that SBC heads can be adapted by adding the coolant holes and changing up the manifold bolt pattern. Is this really practical?

With the kind of power you're talking about i'm not sure what is or isn't practical to you, lol. Besides the manifold deal, check out the thread in advanced tech about the 18Xs. Talk to Bret about them, he's been poking around on a set and has some good comments. Damn near 18* head power with most of the comforts of 23* stuff (no offset valvetrain components, can use a hydraulic roller cam, standard exhaust ports, etc). KTamez would also be another great person to talk to about them (he had a set on a 396 LT1).

Even with how well they flow out of the box (325cfm, 2.14 intake valves), you might not even need to touch the ports to make that much power on lower boost than what a worked 210 or 220 head would. And for what you get, the prices i've seen on them are a steal.

Just stirring the pot o' possibilities.... (really i just want to see the potential in this combo, i've been looking at something like this for about 2 years now)

Yeah its all about pressure ratios, not cubic inches. Same reason why people ask, how come a Supra can make 1000+rwhp with a certain turbo, but on a big 454, that same turbo is lucky to make 750rwhp...hehe. Heck check out the 306CI mustangs running the T88's and making WELL over 1000rwhp.

Yep, smaller displacement puts the turbo into a more efficient pressure ratio for a given amt of airflow.

Jason, no question the 18X heads are bad, but I'm not sure if they can be massaged to work with an LTX intake. I'm sticking with my LT4 intake and I would like to see a set of 18X's be adapted to it.

Jose

Yeah, heck look at Jim's car also, another case of a small cube LT1 making HUGE power. Turbos like rpms and high PR's. I'm working on this 355 to add 4 bolt splayed billet caps, main girdle, and hard block. I think an LT1 block is good for alot more then we think. Heck Rick's LT1 is running a HUGE 106mm with a small 398ci LT1. That motor has made 1280rwhp and will be making ALOT more in the near furture. I think with the right bottom end components these motors could touch 1600-1700hp. Heck look at Alan dudley's old SBC motor. Its just a standard SBC which we know is weaker then the LT1 blocks and that motor was making 1300+hp on the dyno at Young's Performance. I think with the advent of the turbo into the LT1 market, we are just beginning to see what these motors can really do.

Jose

Jason, no question the 18X heads are bad, but I'm not sure if they can be massaged to work with an LTX intake. I'm sticking with my LT4 intake and I would like to see a set of 18X's be adapted to it.

Jose

I guess the only way to do it would be with spacers (one fine individual has done this on GM 15* heads with an LT4 intake), but that'll probably be a lot more work than ya'll want to throw at it. I guess i'll have to be the test rat for the PTK/18X/LT1 setup :D Now where did i leave my checkbook....

My main concern is getting the bottom end not to walk around. A good set of AFR's will take you to 1300+hp. Rick has already demonstrated that.

Jose

True... took 8500rpm and ~22psi to do it. Monty William's 427 SBC 'vette (old school) is making 1200/1200 with 18* heads at 17psi, but only needed about 6500-7k rpm to do it (he's got a lot of money in that engine though). Better heads do make it easier. I like easier... too bad easier is almost always more expensive lol. :D

So Mike, what's the future plans for the car? 8s?

Mike, if you are interested.....I have a set of Canfield LT1 heads forsale setup for high hp turbo applications. Thick deck, Iconnel exhaust valves, ported, o-ringed, etc.... Made 550rw on just 7psi.

email or PM me if you are further interested. jhsformula@aol.com
Jason

My main concern is getting the bottom end not to walk around. A good set of AFR's will take you to 1300+hp. Rick has already demonstrated that.

Jose
so Jose you saying if i stay with my current 383 and go ptk kit i wont make as much power as i would of with 355? just sound like too much money to build another buttom end

Oh you will still make plenty of power (800rwhp+), BUT the higher you can get the PR on the turbo (to a certain point of course) the more efficient the setup will run.

I have heard that the casting quality of the TF head is much better than the AFR, with better cooling passages AND the thick deck also.

Is this true? Especially the coolant passages part.

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... to be honest with you I've become [such] a firm believer of the 355 configuration ...
Jose


I would be interested in your opinion of where the advantage lies in the 355 setup, as opposed to the 383. Clearly, you are seeing convincing empirical evidence. If you have thoughts as to the "whys" however; that would be great. Specifically, there was a lot of talk on this thread about rpms. Do you think that's what it's really all about, meaning it's more of a turbocharger and perhaps centrifugal supercharger issue than a boost issue. Or do you think there's more too it?

Is this true? Especially the coolant passages part.

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I would be interested in your opinion of where the advantage lies in the 355 setup, as opposed to the 383. Clearly, you are seeing convincing empirical evidence. If you have thoughts as to the "whys" however; that would be great. Specifically, there was a lot of talk on this thread about rpms. Do you think that's what it's really all about, meaning it's more of a turbocharger and perhaps centrifugal supercharger issue than a boost issue. Or do you think there's more too it?
from what i understand theres gotta be more to it, cuz look at joe o and his 387 cid lt1 is reved up to 8k, dont think you can rev a 355 much more than that, so theres gotta be more to it, but of course a 355 would rev quicker.

Oh you will still make plenty of power (800rwhp+), BUT the higher you can get the PR on the turbo (to a certain point of course) the more efficient the setup will run.
Jose,
thanks for the quick reply.
Is there any possible way some of us can get a hold of the Gen1 kit with a t88??, i'm still a strong beliver of having a t88 especially with a strocker motor.

I kinda see where Jose comes from on the 355 vs 383 argument. In theory, a 3.48" stroke will impose smaller g-force loads on the bottom end than a 3.75" stoke (longer moment arm). That and the smaller stroke can allow pistons with more CH for more strength. By geometry, smaller strokes will also give slower mean piston speeds at any rpm. And finally, with the LTx block, you don't have to remove any material from the bottom end to clearance a longer stroke when you go with a 355. But to the extent that these "benefits" really work or exist, no one knows. The fastest LT1 right now is running a near 400 cubic inch configuration. But from another perspective, the only replacement for displacement is boost. The difference in power between a 355 and a 383 might be made up by about 2-3psi of boost. But there's no absolute proof of this. Just build what your budget allows.

Jason hit the nail on the head. I like less rotating stress on the bottom end. Of course Rick's car is defying this since its a 398ci, but its not daily driven either. Thats the only reason why I prefer a 3.48 stroke for daily abuse. Now I will be testing this myself as I have a 383 currently in the car with the T88 ;) and a 355 in the works to drop in after the 383 goes. So it will be interesting to see the difference if any. My ideal setup would be 355, billet caps, half hard block and a main cap girdle. I am beginning to think well over 1500+hp can be done with the LT1 block and a nice turbo setup. I am thinking about trying to find that limit. ;) Of course mine will be a street car only...I'll leave people like Rick to stomp on the LS1's...lol. My only crutch I see is the intake, which I would like to keep and push to the limit and the heads that will work with the LTX are limited. So with that being said, a custom sheetmetal might do the trick and 227CC AFR's or the 215CC RR AFR's. I am beginning the works on a sheetmetal LT1 intake that will be affordable...

Jose

Ok, as far as turbos and displacements are concerned, this is why smaller displacements can be more efficient.

If you look at a compressor map, you will see that turbos are inherently more efficient at higher pressure ratios.

Take a supra for example. It is a 3 liter engine, that can make over 1000rwhp with a 76mm turbo. Probably with around 40+ pounds of boost. This is operating the turbo in its sweet spot. (and yes a 4 valve head helps too)

Take a 76mm turbo on a 350ci engine, and you will actually have a harder time making 1000rwhp, because the larger displacement will move 1000rwhp's worth of air at a much lower pressure ratio, and at a much lower efficiency range of the turbocharger.

Basically, in almost any turbo setup, displacement will have great effect on spool time and rpm range, but the turbocharger system will be the greatest determining factor of absolute possible horsepower. (within reason, and assuming that the cylinder head(s) and camshaft(s) are designed around the same goal)

That is correct.....turbo efficiency is the key, not cubic inches (up to a certain point). Some of the LS1 guys keep building these monster cube LS1's, when their is no need for it on a turbo setup.

Jose

That is correct.....turbo efficiency is the key, not cubic inches (up to a certain point). Some of the LS1 guys keep building these monster cube LS1's, when their is no need for it on a turbo setup.

Jose

Thanks for the good info. Espcecially the information about pressure ratios as of late. I was thinking of a turbo 383 but with your information about pressure ratios over I'd say the last several months , as well as your customer results, I think a 355 sounds good. I knew that smaller motors were also more efficient anyways , but I wanted the extra cubes just for non boost response. I knew looking at turbos, and cars from supras to mustangs, and many other makes , that turbos don't have a problem making power on small motors. I was just worried about low boost response, But I imagine a lower compression (8.5 - 9:1) 355 with a mild cam could have nice throttle response when not in boost.


Too you guys that insist on bigger motors more power to ya (no pun intended) , just cram a bigger turbo in there :D , that way , to that 91.5 mm your stroker will still be a "smaller engine" vs having a T88, and it can be run at a higher efficient pressure ratio on your 383 - 400 . Cubic inches and higher efficient pressure ratio. If you could make it fit, a 383 with a large frame T88 or similar ,or a 91.5 doesn't sound too bad. :D

Jason hit the nail on the head. I like less rotating stress on the bottom end. Of course Rick's car is defying this since its a 398ci, but its not daily driven either. Thats the only reason why I prefer a 3.48 stroke for daily abuse. Now I will be testing this myself as I have a 383 currently in the car with the T88 ;) and a 355 in the works to drop in after the 383 goes. So it will be interesting to see the difference if any. My ideal setup would be 355, billet caps, half hard block and a main cap girdle. I am beginning to think well over 1500+hp can be done with the LT1 block and a nice turbo setup. I am thinking about trying to find that limit. ;) Of course mine will be a street car only...I'll leave people like Rick to stomp on the LS1's...lol. My only crutch I see is the intake, which I would like to keep and push to the limit and the heads that will work with the LTX are limited. So with that being said, a custom sheetmetal might do the trick and 227CC AFR's or the 215CC RR AFR's. I am beginning the works on a sheetmetal LT1 intake that will be affordable...

Jose
anyway to make the excell(victor jnr) type manifold work with forced induction? never seen that done

Rick's car is using a Vic Jr manifold. So yes it can be done.

For those that are trying to understand more about turbos and cubic inches try reading our compressor map section, as it will show you what happens with big cube motors and improperly sized turbos.

Jose

There are reasons people use aftermarket and Bowtie blocks to make huge hp. A 1,500hp stock block will be a time bomb. Now, if you nver use it at full boost or wind it up, it will last. But in that case, you haven't proved anything. High performance street use can be tougher on a motor than track use. It will see many more duty cycles and is likely to be beat on when hot, going uphill, etc. All of which is quite different from a few seconds of WOT under optimal conditions at the track.

As far as a 355 vs. a 383, I can't believe the differences are big enough to be an issue either wrt hp or longevity. I'd worry more about the bore than the stroke if planning on making huge hp with a stock block. That's why mine is 10 over and not thirty.

Rich

So exactly what kind of PR are we talking about to get to 1000rwhp efficiently? I have narrowed my selection of compressor, I am leaning toward 2 GT4067s turbos from precision. With a small block chevy 383, 230-230 cam on a 114 lsa, and LE ported Trickflow heads, what type of boost would I need to run to get there. At my elevation, 25 psi comes out to a 3.06 PR, would that be in the efficiency range (I will be using a water/air intercooler with it rated at .7 psi drop at 120lbs/min of flow).

Thanks

That is correct.....turbo efficiency is the key, not cubic inches (up to a certain point). Some of the LS1 guys keep building these monster cube LS1's, when their is no need for it on a turbo setup.

Jose

Harlan's firehawk is the perfect example of that.... 346 (or 348?) LS1 running 8.20s at 170-something mph. Crank the boost up!!!