234 heads on a 04 GTO

[wraith221304]

what's up guy's need a little help? I have a 04 ls1 heads and im switching to ls2's 243'2, do i have to change my push rod's when i change my heads i mean are they the same size?

[JAX04]

are they p&pd? just curious,

on a serious note, they milled??

[cammed goat]

I have heard discussions about the 243 swap, but never heard anything about having to change pushrods.

[wraith221304]

Yeah me to that's why i am was asking.

[wraith221304]

O and no that are not milled like there are, they'll raze it up from 10.25 to 10.5

[cammed goat]

PM moderator Sarge. He would know.

[Sarge]

what's up guy's need a little help? I have a 04 ls1 heads and im switching to ls2's 243'2, do i have to change my push rod's when i change my heads i mean are they the same size?

Sorry....I didn't see this post.

You did not say anything about a cam upgrade. So I assume your just bolting on the 243 heads. I can tell you the 243's flow a bunch better. Expect between 25-30 more HP from just a headswap. While I had the heads off I would go ahead and install a set of LS7 lifters and pushrods. Get some decent springs and new tray. Then when you upgrade your cam it is only a cam swap.
Any head swap check your pushrod length. I use these.... http://www.texas-speed.com/shop/item...d=913&catid=51

Me....I would get hardened pushrods at the least and slip a LS6 cam in there while I was doing all this

But to answer your question specific. The LS7 cup is .050 higher than the LS1. The LS1 comes with a .100 preload....without changing the pushrods you will be at .050 preload.....within the safe zone. However...take into consideration head gaskets, milled heads etc....and you damn better check (measure) your pushrod length. Just common sense. I don't think you can even buy LS1 push rods anymore. GM install LS7 stuff in everything now.