I've done searches on raising the compression on TFS heads and everybody mentions milling, has nobody used cometics with these heads? From everything i've read it's better to decrease gasket thickness first and then mill accordingly.

 

some people are scared of the cometics because a few others have had leaking issues. with a clean, flat block with both deck surfaces flat and clean they should seal without issues. but there are instances where both them and gm mls gaskets leak as well but very rare. imo i would use thinner gaskets for the tighter quench over milling or possibly do both,depending on how much you want to bump up your scr.

 

Yeah, i've read posts about the leaking that your talking about. So if I went with the
.040 cometics on the TFS heads what would my compression be? I've read that they come with 10.6:1.

 

i think you will raise scr around 3.5 tenths of a point. i think actual compression on a stock ls1 is around 10:4 or so so it would be somewhere around 10:7 with a gasket change give or take alittle.

 

when you buy the TFS heads you can get any cc chamber you want for the compreson you want.

 

I have 64cc TFS 215's, thats the way they come unless you tell them different. I use an .040 cometic with no leaks. using .006 outta the hole, we didnt measure, it comes to 11.03:1 compression

 

So with out of the box TFS heads and cometic gaskets your at 11.03:1 compression? No milling? That's about where I want to be. What cam are you running with those heads?

 

Sorry, just saw that you have a SI7 cam. What is it, haven't heard of that? That a pretty radical cam?

 

Its a Speed Inc. cam, 238/244 .605/.612 110 mine has no advance

 

Man, that's some awesome times your running with those heads and that cam, and that's all NA? I'm definately gettin' those heads. Although, mine is just a street car so I'll get me a medium size cam, maybe the TFS stage III cam or the Vengence VRX3.

 

thanks and yes its all motor. Either of those 2 cams you listed should work awesome with these heads for a street app.