Belt rubbing water pump

Appreciate the pics kuda. The double-groove alt pulley - this was an AC engine but the PO removed the AC and I guess just hacked together a pulley set-up that would work. Sounds like that's a common thing people do.

Also, clearly my alt. mounting is NOT the same as what you have, so I'll probably replace that. Mine just has a single pivot on the "engine side" of things, which means there's really no way it can be tight enough without a ton of deflection.

So my question is, is it worth it to just replace all of the pulleys and brackets to have the right set-up? I assume the water pump isn't bad but how tough is it to swap out a crankshaft and alternator pulley on the car?