GM used those "barrel bearings" in a number of applications including the rear axle hubs on 3/4 & 1 ton trucks. They were in a 66 C-20 that previously I owned. I also saw them recently in a 4:10 rear end we installed in a 55 3600. The differential was from a 72 C-20. I think they may have been made by New Departure which was a GM component.
Fred
