I just went and looked at the pinion on the rear end that came out of the 1957 lcf 2 ton GMC 350(f350)with what we believe to be a 347 Pontiac but have not found the numbers yet for the engine. When the owner and I picked up the truck,on the firewall was marked in grease pencil (original engine 1957 347 Pontiac). OK,here's the numbers on the pinion which looks to be brass (but don't quote me on that) 823 3890028 nk On the pinion housing was 3826-1-202 On the 3rd member was Timken 4053 C2C-c 5800-m-429 As stated before the rear end had no axles and pinion and bearing is wasted. (2 speed rear) What rear end will fit in this truck and needs to pull a 12,500lb sailboat and a decent speed,not fast per say but fast enough to not cause a traffic problem. Asking the (GURUS)out their on their opinion (you guys) footnote the numbers are barely there on the pinion. Thanks in advance and have a BLESSED day Mike