You can get replasments at the auto parts store for $100-140 using the OEM #1105500, but you most tell then that it has an Isolated ground and for an ambulance or limo aplication to get the 100 amp model, otherwise it will most likely be a 70-75 amp unit either way it may not last with their inferior quality rebuilts and parts. Electrical issues are the CUCV Akilis heel(?), and they can have a domino effect if not address early and properly.
I just had both of mine rebuilt last month by an Old timer electric motor shop with primium parts $120 for; #1 ALT. bearrings, bushings, rotor, regulator, rectifier and diodes. #2 ALT. $90 as the rotor was up to specs. Some people in SS did it then self for less.
The man told me the winding in this is as good as it gets with the exception of a couple modern High Output premium and high-end foreign ones.