LSOHOLIC

iTrader: (3)

Hello, I'm looking for some input on which heads to go with. (Quick rundown) Forged 370, F1-R, iron block, C5Z, 6 speed. I'm in the begining stages of the parts collection. My question basically comes down to this, will I see a real performance gain between the 317's or the L-92's. Basically a 9.5:1, spinning 7000RPM @10-14 PSI setup. I own the 317's already so that right there is an advantage. Its going to be a semi-budget build. Not trying to spend every dime, but willing to spend 1,200-2,000 $$.
SO, out of the box comparasion 317's vs L-92's
or lightly ported 317's vs L-92's
Also deck thickness to be factored in. What this really boils down to is catherdral vs square port in a boosted application.
Any serious input is appreciated, Thanks

COPO9560

You should look at WCCH's Stage 3 L92 heads. Flow numbers are very good, should run well so long as you don't get too high with boost.

Shooting for 10-14 psi with a 370, curious why you choose F1-R blower over F1A.

LSOHOLIC

iTrader: (3)

I'm not a procharger expert but the intake side of the F1-R blower seems to be the advantage. R meaning reverse. Intake facing forward. I talked to tech at procharger and thats what they recommended for my C5Z setup. But I would love to here your opinion. Like I said, I'm no centrifical expert.
Thanks

dreamls1

iTrader: (25)

We are going with ported L92s.

robert miller

You will love this unit on the vette man.... It will pull like crazy and top end is wild....

6.0ltrS10

iTrader: (2)

Shawn at VA-speed told me the L92's are weak and prone to cracking. I'm not sure what boost level though.

So.jerZ-28

iTrader: (20)

I'd like to know the answer to that too.^

OUTLAWZ RACING

iTrader: (9)

easy trick flows 220, flow good and great deck.

BigRich954RR

iTrader: (1)

LOL that should be all you need to know.

But i wouldnt push passed 700RWHP or 15 psi with the l92 heads

Bob@BruteSpeed

iTrader: (16)

I'd spend a little more money and go with AFR 225 heads. You have a much thicker deck surface, and you'll probably be at least running 14 psi with an F-1R. With the AFR heads, you won't have to worry about pushing water until you're up at 20 psi or so of boost. Bob

LSOHOLIC

iTrader: (3)

Great info thanks guys

LSOHOLIC

iTrader: (3)

Ok, lets try a new angle. Lets say I will make 750 at the tire with the 317's. How much am I leaving on the table buy not stepping up in the head department ?? Of course boost, CI, RPM, blah.....(you get the picture) being the same. Be it cathedral or rectangle port. I'm trying to put a dollar value on the HP left on the table. Example if I put on the top dollar AFR's and pick up 100 HP at the top of the RPM's, well thats hard to justifiy for $3,000.00 tag. And I think 100 HP is a bit high, but thats why I posted the question. So lets here what you think.
O' yeah, one angle I can think of would be by stepping up to better heads, the deck tends to get better. Which would lend itself to more boost. AKA more HP. As long as detenation is kept cool

52172

iTrader: (2)

as cast Trick Flow heads will get r done also and you will save about 800 dollars over the afr's. You cannot go wrong with the afr's though....

AES Racing

iTrader: (6)

10-14 PSI, i'm going to assume with a 5.00" pulley? 15psi I recall being the lowest i've seen an F series head unit run at max rpm (6500)

otherwise, We still have 317 heads in stock, ported, 5 angle valve job, 2.02"/1.57" stainless valves, dual springs. $995

jimbob

iTrader: (4)

If your not going to run allot of boost (deck thickness issues) then just have those 317's ported...

Here's a Boost formula (I think it's the right one...well it works) to give you an idea.... engine flywheel hp X (your boost level/14.7) + engine hp= new engine hp. Other words for example your engine makes 400 (off boost) X 1(14.7 lbs for example) +400 (original flywheel hp)= 800. So if you get 425 flywheel (with a better set of heads) than this would equal out to 850@14.7lbs of boost....So, yes a better set of heads will help. But.....You might already be maxed out on your turbo system where you'll just make more heat with no real hp change....If you have a blower you'll need to pulley up to get back to the original boost level, or you'll see very little difference in hp. Even @ 14.7lbs you see that you would only gain 50 (everything being correct). Most cars make 20-25rwhp per lb of boost. So, in therory an extra 1 1/2 lbs of boost would equal the same amount of flywheel hp. As you go big though this restriction to air flow (your heads) will cause more and more hp loss. It all depends if you want all available power out of your set up or you want to save the money and just run a little more boost to compensate....

AFASTYZFR1

iTrader: (55)

Love my AFR 205's

bad6as

iTrader: (17)

tfs c&c 225's on my turbo build looking for 1k flywheel

fatmat80

for my d1 build i went with prc 2.5 ls6s..they are working fine so far for me i made a max boost of 13.7lbs at 6500 on the dyno no issues with lifting...keeping my fingers crossed...If money was not an issue i would go with TFS ported by TEA..