I have a 78 f250 with the 400ci with a 4 speed manual, im just curious, does it have the dana 60 in the rear?
look on the rear cover of the gear houseing,it will say what it is,may be inside also,probly is.
If you still have a VIN sticker/plate on your door frame, it may list you axle. Example, "Axle B3" is a Dana, I'm speaking from 1985 though.
chances are it's a sterling 10.5 . My buddy has one on his 1977 F250 demo derby truck, it's been through 9 3/4 ton truck derbies and never broke a single axle. they are tougher than hell!
Search Ford F-250 Questions
Ford F-250 Experts