I've used a copper head gasket in the past with just a copper gasket sealer, but it never worked. for my new turbo set-up i bought a copper head gasket again, but wanted to do o-ringing this time around. First can i o-ring both the head, and the block? i read about most people doing one or the other mostly the block. I don't see why you couldn't o-ring both. Unless its because of having a cast iron block, and aluminum head since they expand, and contract differenly you might not want the gasket tied in to both the bottom and top end. I could see how you might want a little flex between the two. Any one here running a copper head gasket with high psi levels? Or anyone have any insight into o-ringing? Last what are you guys using for head gaskets for high psi if not a copper one? thanks