Generation IV Internal Engine - questions about LS2 heads?




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bigwill1983
03-15-2009, 01:43 AM
Are the LS2 243 heads better that the 317 heads the come on the trucks? if they are can someone tell me the diffrence between the two.


SweetS10V8
03-15-2009, 08:10 AM
The #243 has a smaller combustion chamber, so it will produce more compression than the #317.

Ive read that they have the same intake ports and exhaust ports, but have no hard evidence.

Some #243 heads off of LS6 Corvettes come with lightweight valves. A lot of them have the normal valves.

#799 heads and #243 heads basically identical also, just different numbers. Ive read about cars with a #243 on one side and a #799 on the other from the factory on newer LS2 cars.

bigwill1983
03-16-2009, 06:36 PM
okay. so would the 317 be better in a heavy body car? since i see that the 243 comes in the corvettes and the 317 come in the trucks.


sroach20
03-16-2009, 06:51 PM
depends on what its going on. if you want boost go with the 317s, if you want compression go with 243s.

Shawn @ VA Speed
03-16-2009, 08:18 PM
while the 243's and 317's have very similar ports,the combustion chambers are much more efficient in the 243's.any n/a engine would benefit with the 243's over the 317's

bigwill1983
03-17-2009, 12:23 AM
doing a project. put lsx motor in an 1996 impala ss. So the 243's would be better for me than then the 317's for this project? even tho im using the cast iron block?

Sid447
03-17-2009, 07:45 AM
doing a project. put lsx motor in an 1996 impala ss. So the 243's would be better for me than then the 317's for this project? even tho im using the cast iron block?

If it's a 6-litre iron block, fitting 243 heads could put your static CR at around 11:1 depending what pistons are fitted.

Note: #243 heads from the LS2 have the normal steel valves, same as LS1.

Only the ZO6 LS6 5.7 engine from 2002 to end 2004 had the lightweight valves fitted in their #243 heads.

bigwill1983
03-17-2009, 09:41 AM
yea it's the 6.0L. and the the pistons are stock. no changes to the bottom. thinking about changing the cam to a stock ZO6 cam that im looking at getting. So the 243's are better? so for Performance the i should go with the 243's off any corvette 05 and up and get push the 317's aside?

Sid447
03-17-2009, 09:49 AM
yea it's the 6.0L. and the the pistons are stock. no changes to the bottom. thinking about changing the cam to a stock ZO6 cam that im looking at getting. So the 243's are better? so for Performance the i should go with the 243's off any corvette 05 and up and get push the 317's aside?

There's two types of stock pistons for the 6.0Litre iron block.
The LQ9 version had flat-tops the LQ4 had a small dish, IIRC it was -6cc or similar.
Regardless, the 243 head is a better stock head casting.

bigwill1983
03-17-2009, 01:47 PM
when i got the block the pistons that was in it had a + type shape on it but one had a hole in it so i brought a set of 8 new but these are flat topped so that mean i changed it from a LQ4 to a LQ9? thanks on the info bout the heads im going to go with the 243's.

sroach20
03-17-2009, 09:23 PM
those are both dished pistons. the second ones are the same style i have. youll still have an lq4 with 9.4:1 compression unless you get some that are completely flat.

bigwill1983
03-17-2009, 09:45 PM
okay. So the LQ9 is good for a turbo and the LQ4 is good for a supercharger? or is it the other way around?

sroach20
03-17-2009, 09:48 PM
lq4 is good for turbo and supercharger, lq9 is good for spray. the lower your compression the more boost you can run (within reason).

bigwill1983
03-17-2009, 09:55 PM
good. i rather go with a supercharger. not a turbo fan and spray out of the question. thanks.

Sid447
03-18-2009, 01:16 AM
Fitting 243 heads,

On with those pistons is going to give you around 10.5:1 static CR.

bigwill1983
03-18-2009, 01:41 AM
would a stock ZO6 cam be good with this? im thinking about getting one for rite now untill i can find one later?

bigwill1983
03-18-2009, 04:48 AM
do any body knows the price,part number or where i can get an LS2 Camshaft Sprocket with the 1X signal ?

Sid447
03-19-2009, 10:06 AM
would a stock ZO6 cam be good with this? im thinking about getting one for rite now untill i can find one later?

Yes, and blower friendly enough too.

Why do you need the LS2 cam sprocket? Is this for the LQ4? If so you don't need it.

bigwill1983
03-19-2009, 01:14 PM
i have the timing cover that has the cam sensor in the front. and the cam im tryning to get needs the camshaft sprocket thats reads from the front and it has to be for a 1X signal so that it is for a 24 reluctor wheel. but i found one.