Need advice on 12V conversion alternator

[meck]

When I bought my 640 fifteen years ago, it had already been converted to 12V with a one wire alternator. Now, the alternator is making a squealing sound, and it sounds like its coming from the bearing when I listen to it with a stethoscope. I can't find anything on the alternator to identify what it is, so can anyone tell me what I need to buy to replace it. Online, I see all kinds of one-wire alternators advertised and discussion/arguments about them. I would rather get a recommendation from some of you all with experience. I appreciate it.

 

[MeanGene1]

The ones sold on this site work very well, and their claim that they will start charging at low RPM is valid. I got kits from here for my 8N and my 450, brackets, pulleys and belts all good

 

[Eman85]

Most likely a GM alternator, pic would help. Easy to disassemble and replace the bearings and every other required part. The internal regulator is what makes it a 1 wire alternator. A 3 wire will work and would only require 1 extra wire with a diode from the ignition circuit to work and they are available at every parts store.