Guys, picking up my car from the shop today. Had head gaskets replaced. The old gasket he took out of the car had like 6 or 7 holes blew through it and damage along the holes for coolant and oil. The machanic is telling me im getting really bad detonation. The thing is i was never getting this before and all the parts are brand new, was it just because the gasket was on wrong and it just got really blew out, or do i have bad detonation? I have no boost retard on their but my tuner tuned around it. I just cant figure out why all of the sudden i wuold be getting pre det?!