Front 60s - as far as I know - were all 35-spline at the diff, which is what we'd be comparing if you swapped to a 14BFF or 14BSF chunk for steering.
Dually is actually the housing you want if you want true beef. They have thicker tubes, thicker diff housing around the tubes (I believe...), and are the same backing plate to backing plate in width. The difference comes from the extended length spindles.
EDIT: I'm trying to find out about the dually differences and it being the desired axle for making steer...