it depends on what kind of pistons the 520 has, they may not be compatible with the chambers, like a E head won't work with I pistons, the pistons will hit the head, a I head on E pistons you have really low compression, which is fine if you wanna stick on a turbo and blow 20# of boost but would suck otherwise

Originally Posted by
Fraz06
Hey guys, Would a m20 cylinder head from a 1990 325i sport fit a 1989 520i m20 engine ? without any problems ?

guys
Fraser
all america wants is cold beer warm cat and a place to take a poop with a door on it