If a bearing is noisy why don't you simply replace the bearing, it's not all that hard. Mechanics these days don't seem to want to repair anything. I know for a fact that whatever alternator you have, it's not that all that hard to do. The bearings are also not all that hard to come by any place that sells bearings should have them on the shelf. (like Bearings Inc) While you're in there replace the brush assy.
Note, I did recently come across an alternator that I couldn't replace the bearings in.
It was an Italian alternator (Marelli)
on my British car (Land Rover). It was manufactured in such a way that you couldn't get the housings apart.
You probably have a J180 mount which was pretty much everything until the last few years. If it has one long bolt going through two ears and one ear on the opposite side it's probably a J180. There are only two variations, the distance between the upper and lower bolt is different. On many engines they will interchange. With a J180 mount usually the belt is tensioned by swinging the alternator, but it may have a fixed mount with a separate tensioner.
The picture that 2kool4skool posted is a J180 mount.
There are many manufacturers of heavy duty alternators, Delco, Leece-Nevile, Bosch, etc. The main difference is amps and the later ones like the Delco 28SI are for high underhood temp problems.
A pad mount alternator is bolted to the engine with four bolts and uses a separate tensioner.