If my memory is correct ford offered two different Dana 60 H.D. axle tube diameter, 3.0 and 3.250, maybe even a 3.125 width earlier I've used all three, I prefer the 3.0 or the 3.125 for the weight savings The shorter , narrower axle tubes, the less weight
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)