belt

Howdy! Got a weird problem. I need to replace the alternator, but the old one and the belt I have is a 4 ribbed system. However, the only alternators I can find now take v belts. I can't find any compatible alternators that use the 4 ribs Any ideas??

I'm using a belt tension tool to try and loosen tension so I can remove alternator. I pull towards the front of the vehicle but it only moves so far. It's like it just dead stops and only slightly loosening. Not even close to being loose enough to do anything. I am definitely not hitting...