Bad G04t

I was in the midst of installing my lpe GT2-3 cam on my 04 GTO when I found out my head gaskets were blown, luckily the engine was halfway apart anyway so I pulled the heads.

so I called up my machine shop to ask about getting some valve/porting done to either my heads or some 243's while they were off. turns out he has a set of very clean low mileage 317 truck heads at his shop that he can port and mill for me

he was figuring he would mill them about .020-.030 to get to stock CR and clean up the ports a bit and do a valve job on them

I know people use these heads for FI since they lower CR with the larger chamber, would this work well on n/a with the gt2-3 cam if he mills them down? anything special port / polish wise i should ask for

anything I will need to do special for this set up, would i need diff length pushrods, and what head gasket do i need? will ls2 gasket work since they are both 6.0? would a thinner gasket help also .045 or .050 possibly

I realize 243 heads may be better than these heads for an n/a application but will this work since they are available and inexpessive.

NastyC6

iTrader: (77)

they're the same castings. just thicker deck,72cc chambers.Gm gaskets r perfect,35 bucks each. u better measure for pushrods. make sure ur machine shop measures each head when they mill them,then maybe cc them just to make sure,n yea u will need shorter pushrods.

regency

iTrader: (15)

deck is not thicker!! the chamber is opened up more. You can do that but have him check the CC of the chamber to make sure its right and not just a guess. Now, with doing that and having a bigger cam, your going to reduce the PTV clearance alot. So your also going to have to check PTV. Also to get you back to stock CC he is going to need to mill atleast .030!!! Let me also give you this to think about, the more you mill the less it takes off so the .006/per cc that happens with just a few cc's isnt going to happen that way with .030 so he may need to take more than that off.