The one wire alternator is expensive and usually not in stock at your random parts house. Unless you have to have a one wire, I'd use a GM 10si or 12si.

I prefer the GM 10si or 12si when I need to use a GM alternator. They are affordable and available in stock everywhere in case you ever need to do a roadside repair, easy to hook up, and come in a variety of amperages.

On an off-note, I have an early Chrysler alternator on the '62 Chevy 283 in my Model A. Not many people do that, I bet!