I'm currently running a b1 block with a p8r head with a ls hg. When I got the head rebuilt I wanted to mill the head .030 but the machine shop said that they didn't recommend it so I left it at that. Car runs strong and I'm planning on boosting in the near future. Am I using the correct hg? Comp test results are 150 psi on all cylinders. Is that because of the lower comp the p8r head makes? I've never even heard of the p8r head till recently so sorry if I'm a Lil newby-ish.

 

Yes, you're using the right head gasket. I doubt the head alone is lowering your compression test results that much. Do a leakdown test.

 

its probably due to the larger combustion chamber of the p8r head.

go to the leakdown test and see what that says