My A/c Pulley is all locked up I think keeping the belt from turning. Shoud the center of the pulley spin freely when the belt is off, and can I use a smaller belt to bypass it without screwing up anything else? Thanks.

on the genII 3100's, you can use a smaller belt.....not sure about the gen I 3.1L's. And yes, the center (clutch) should spin freely.