My "new" '74 Duster- or why I need a project like a hole in the head

Thanks to the write ups you and goldduster318 have made I'm making the move to a Cougar twin fan set up. Found one on Ebay with the wiring pig tails (try finding the harness now days) and ordered up a controller. Need some info on the Tuff Stuff 100 Amp alternator your running. I have a lead on a new black mopar unit that the owner doesn't know any thing about. Any way to ident the 100 Amp unit over a stock 60?

PS. Is your March pulley set up six grove?