camshaft for mild 340

Late to the party but I get 9.3:1 static CR with 71 cc unmilled J heads, PT8553 head gaskets .050" thick and 4.18 " bore hole, and stockish high compression type pistons with 2 eyebrows and .013" out of the hole. The 1 unknown is if these are the 2 or 4 eyebrow pistons. With 4 eyebrows it could be 8.9:1. (But I doubt that they would be .013" out of the hole for the lower CR 4 eyebrow pistons.)

So 'medium'-ish compression at best.