Hi. I will put an ECS NA cam less than 600 lift and a set of 243 heads prep by TEA with stock 64 chambers. I want the compression to be at 11.1 or more by changing the gaskets because I do not want to shave the heads. I was told by texas speed that by running .36 cometic I would be at 10.9. Later I see that cometic had C5475-030 (.030") and C5475-027 (.027"). can i run them? what compression would be at .30 and at .27? can I put them without damaging anything. My motor is stock(crank, rods, pistons). PLEASE HELP ME

 

Don't go any closer than .040" on the Cometic. With a .040" gasket, you're quench is around .032-.034" and that's as tight as I would ever run it.

Why not deck the heads? I had TEA mill mine down to 62, which was about as tight as I could go with my EPS cam without flycutting and running a Cometic .040". Now I'm looking at a rebuild on my stock block using Diamond 0cc Flat Tops and Compstar 6.100" H-Beam rods so I don't have to mill any more and mess up the port-matching on my FAST 102.

 

Really you can't safely go to anything less than a .040 gasket on most ls long blocks. Just mill the heads Christ mine are cut clear to 48cc, I think you will be fine with a light mill