I'm not sure but I think the factory compression ratio is 9.0:1. Correct me if I'm wrong. Does anyone know if it's ok to run 9.5:1 compression with 12 lbs of boost on 93 octane without detonation? Also, does anyone know how thick factory head gaskets are? It's on a 03 gt. Thanks.

 

this question comes up a lot so try the search function.

12psi of boost is fine for 9.5:1 compression. its all in the tune.