Looks like your water pump pulley is way too wide for the belt which will cause to slip. I think Cletis is right. I mess with GMC as well as Ford y blocks. I'm quite sure that a Y-block ford will work and they have about the same belt width as your alternator. It seems like you have a narrow pulley on your vibration damper too. Fans appear on eBay ever so often. A shroud will help a lot. We used to build them out of 14 gauge cut the size of the radiator to bolt on the radiator mounts. Then cut a hole about an inch larger than the fan diameter and then make a circle out if 1" flat and weld it to the edge of the hole. These old hot water sixes have to be kept cool or they will crack or warp heads.
