Tony,
The 73 and up rear axles were leaf spring units (slightly wider), and unfortunately the axleshafts were 1/2 to 1 inch longer than the 60-72 axleshafts. A swap may still be possible, but it is not a direct fit. I haven't tried this particular swap, nor have I heard of anyone that has attempted it (although there have been a few people who have suggested it).
You also reminded me about the shortened turning radius. I took a grinder to the spindle stops and removed enough to allow it to turn properly. I didn't need to remove very much. If anyone does this swap with the old lower control arm, don't grind on the arm, because it might weaken it. The spindle is a better place to grind because it is in a non critical area as far as stress, and the cast metal is much stronger than the bent sheet metal of the arm.
