Hi Mark, Welcome to the site!
It's even more fun when the broken belt takes out the Tranny cooler lines too!
The AC has a clutch on the front. It may be seized. It should turn freely without the belt on.You could possibly replace only the clutch, to get rolling again. What have you got to lose? I managed to find one on Ebay for my 94 360, with the wide serpentine 7 groove pulley, but I had bigger problems than that
TunerforLife says they are not difficult to replace, it would work. Parts are there over on Ebay.
My 1988 has V-belts, Used I think up until 1993? My 94 is a serpentine single belt. A shorter belt to eliminate the AC pulley? IDK. Maybe. It's a 2 groove V pulley on the AC.
A similar Van without AC, would be nice to look at. Even better if it's a parts Van in a junkyard!
Good Wrenching and Welcome aboard!
You really need a Factory Service Manual! Ebay