spaz1

iTrader: (9)

Hey I was searching for this and am finding all kinds of info that contradict eachother. I thought you could just bolt a set on and go.. As far as i could tell they were the same ports as the 243 heads but with a 72 cc chamber. I read that you need to run a 4" bore for them to work and that the ls6 intake wouldn't work and supposidly the rocker arms are different. Can the people running these heads on stock bore ls1 help me out. I want to drop the c/r and crank up the boost.
Thanks,Chris.

Super Slow SS

iTrader: (9)

Bolt them straight on, I have the ls6 intake that came factory on my car, bolts right up, you will need 6.0 head gaskets but other than that and a change in the exhaust ports (stock manifolds will bolt up, just different shape ports) they are the same head.

sujomatt

iTrader: (7)

^^^^ what this guy said!

mcmillion

iTrader: (5)

^^^^^^Yup, worked for me too!

WS6HUMMER

iTrader: (19)

^^^Same as these guys here, just did mine a week ago.

98Z28CobraKiller

iTrader: (17)

Looks like you are confusing the 317's with the L92's. The 317's are a direct replacement to your stock heads.

NemeSS

iTrader: (127)

the 317 will even work on a 3.78 4.8/5.3 bore

BIG_MIKE2005

iTrader: (116)

I would have to agree 100%

Inspector12

iTrader: (29)

These guys are telling you the truth a 6.0L gasket and bolt up. Although the chamber size is not 72cc they are 65cc chambers if I remember correctly I have a spreadsheet of all the head specs, but don't have it handy so I shot this off the top of my head. I know its real close to 65 though. GL!

conan

iTrader: (5)

One more with 317 heads on a 347ci with 4.030" cometics @ .051" thick. LS6 intake too.

67Firebird455

iTrader: (27)

I have a set of #317's on my 4.8 in my firebird. LSx manifolds/headers bolt right up. Make sure to use the 6.0 gasket and you're good to go!

Pro Stock John

iTrader: (34)

I ran ported 317's, 6.0 gaskets, on top of a 3.910 bore LS6 block. Ran an LS6 intake. Went 9.40. Was happy.

shawn_c992001

They (317's) have 72cc chambers that's the reason why they drop the compression ratio when installed with stock rods & pistons.

lowbirdws6

iTrader: (62)

317's do have 72cc chambers! The one's I have do anyway!

spaz1

iTrader: (9)

Yeah I think that's what happend..

thanks.

WS6HUMMER

iTrader: (19)

I agree.

elias_799

iTrader: (8)

just make sure you use the 6.0 head gaskets, if you use the 5.7 ones they will overhang in to the combustion chamber and that will cause allot of issues.