E30 Zone

if i get a new alternator with a grooved pully to go on a 320 with a V belt on it, is it just a matter of swapping the pullys over???

should be yes, though it would be a good idea to at least have the alternators side by side to compare.
I've not done it on an E30, but i used to use newer Mercede C class alternators as an upgrade from the inferior old W124 alternators.
If the fitting brackets are the same, then chances are the pullys will swap over ok.

hmm, hoping for just a little more reassurance than that lol, its off the same car with the same engine, just the pullys are different i think, but its been a while since i had an engine apart to remember. its onl7y 25 notes for it and its down the road but i dont wanna get it and be stuck even more than i am now lol