Hi, on my friends car, a 94 z28, his mechanic thinks that he has an internal vacuum leak. He thinkgs that the engine is suckin air from the lifter valley, whether through the head gasket, or the intake manifold gasket he doesn't know. Is there a way to check for this without taking the manifold off? thanks

vacuum gauge, compression gauge, leak down tester

If an engine leaks between the intake and the crankcase, it will suck in oil and smoke like a freight train.... a very common cause of mystery smoke in a new motor actually.... if it isn't smoking, it probably doesn't have that problem.

Start by posting the engine's symptoms instead of someone's wild guess about what's causing whatever it's doing, you might get some useful pointers about what to look for.