Ok, fact of the matter is I want 10.5:1 compression or close to it on my newly acquired 6.0. This aint going to happen with some milled 317's, I know that. What combination of heads/head gaskets will get me to my goal of10.25:1-10.5:1? What's the stock 6.0L gasket thickness? Also, if I get a set of 799 or 243 heads, can I bolt them on and go or if they need to be milled, how much? Also, do the 799 and 243 heads flow as well as the 317's?

Thanks

 

243s and 317 have the same cc runners, but 317s have 72 cc chambers and the 243s are 64-68cc?

 

New pistons?

 

Supercharge or turbocharge it, that will get your overall compression up

Like you stated though, all you can do is different heads and head gaskets without getting into the bottom end.

 

Right, the stock shortblock is so nice I refuse to loosen any of the main caps or rods. I don't want to comprimise the factory torque of all the fasteners. I don't need more flow, just compression. I'm doing a high compression mild build. This motor is designed for torque What will a .040 head gasket along with 243 heads yield for compression ratio on a LQ4?

 

I'm wanting to do the same thing and put 243s on my 5.3 and am wondering if milling the heads will help/hurt my compression or not.

Can't wait to hear what someone has to say.

 

here. use this. have fun.
http://www.kb-silvolite.com/calc.php?action=comp

 

just mill the heads down some

 

Mill the heads about .040" and run a thinner gasket.