[LMP]

AM I right if I understand that the A/C compressor is blocked and holds the starter from cranking the engine?....But then, "the next day", you had the belt back on.....there is only one belt here so it needs be there for alternator, power steering.....etc..and unless you have swapped the engine for one from a bonneville, I do not think you are talking of a supercharger.....IN fact, you are really talking about a '94 Transport, hey?
..when you say "it seems to have enough power", I suppose "it" means the battery /starter combinaison....

A damaged A/C compressor can be blocked indeed....but then, when starting, the A/C clutch it not ON.....so I'm a little puzzled here....unless the clutch bearing has seized...

I feel I 'd like some more details...please....