My water pump pulley is a single groove and it lines up with the outermost groove on the crank, does the non-AC set up have a different pulley there? Also, what's the difference in mounting hardware for the alternator?
I don't know if all the pulleys are the "proper" diameter/depth - they all look matched to each other, at least, but I'll have to double check that too. I don't think the water pump is the issue as it didn't rub when the alt belt was tight enough. Just that it had already worn that belt, plus the alt is really loose in its pivot so it's misaligned when tight.
