if you look at my gallery you will see a 1991 f350 4x4 dually with single wheels on the rear. that truck was a 2 wheel drive dually I converted to a 4 wheel drive when it had 12 miles on it
. the rear end on that truck was about 3" wider than the front end. the front end was a factory new f350 dana 60 ft. as far as I know the widths are about the same now so I would say your going to be wider track width in the rear on the dually rear end than the front. you could just swap in a single rear wheel rear end. along with the bed and there ya go. take off the ft. spacers and your good to go.