I am doing a head swap and currently have a set of GM 12575392 copper head gaskets. i wanted to see if anyone knew of a thicker head gaskest available for the 6.0L. i am trying to keep the compression as low as possible for the turbo i am putting on. thanks

 

You can order Cometic head gaskets in any thickness and bore within reason for that motor. You won't alter compression much with just the gasket thickness. Your best bet is to have the chambers cleaned up of all casting material. Then you'd reduce the CR and cut down any hot spots that might happen at the same time. Having the proper distance from head surface to piston top (quench) is a big factor in keeping down detonation. Getting the quench too large will hurt more than the lower CR helped.