Thinner head gaskets will give a smidge up in compression, smidge, but that goes in the plus column. That and good three angle valve job mild cam its gonna be an edge up from what it was. Torque come in low scoot the small car along.
instead of re-doing my heads my buddy has a set on the shelf they were done years ago i'll and never used that have a 3 angle valve job and have been surfaced. i'm sure there wasn't much cut on them but anything helps.. i'm gonna buy them from him. . the head gaskets that came off measured about .032. i found a set of mr gasket head gaskets that measure .028 compressed so i ordered those.
