denscor

Is it possible to lift a head gasket with only 6 psi of boost? Took the head gaskets off car and they looked ok. But they were the graphite gaskets. The middle row of bolts were tight but not as tight as the bottom set. Could have this caused it to lift? The shop that did my head and cam swap does NASCAR motors just wondering if they messed up because everything else looks ok. Had heads checked and they checked out fine. Block was checked also it was fine. Thanks