i replaced the head gasket because of crazy compression numbers......160 100 130 120 125 etc. not in that order though. and it's still low. i bought this engine from ebay and it's JDM so it has low miles. so rings would be out of the picture right? that leaves the valves so i want to use my NA head which DID run before i took it out. is there any difference besides the cams? (which is better anyways) this is a JDM turbo engine swap that doens't run into an NA. please help.