I was driving around today and saw on old 51 (or so) GMC 300 flatbed with a two speed rear end. I noticed that it has a five lug rear end, rather than a ten lug rear end like my 49 Chevy. Also the hub diameter (where the wheel slides on) looked larger. Is there any advantage to this rear end, such as better (faster) gearing or late model wheel interchange that would let you run 22.5 inch rims? I was very surprised that GMC went to the trouble to have a different rear end, when the Chevy unit seem stout enough for most anything. Alright guys, I'm ready to get educated!
(If anyone is interested, the truck is in Tulsa, Ok and I could get a phone number)
