I would run a 78-79 ford d60. Could also the later style hp d60. I ran an 89 hp d60 for a while. Then upgraded to on 07 ford super duty d60. With 35 spline inner and outer axles. Big ball joints. Everything on the 05+ super duty axles are beefy as hell. Other than these newer d60's, I would personally stay away from any ball joint crap. The aam 9.25 that is found under the dodges are decent. But they are not the same size as a dana 60. They are equivalent to dana 50's. You could even do something bad ass and unusual. Like running a low pinion d60 out of an older chevy. But it would take alot of work and would have to run a different tcase. Not sure what year ford change the bolt pattern to their current 8x170mm. The older bolt pattern is the same as ours 8x6.5 but the studs are standard vs. metric. Leaf sprung setup I would run the 78-79 ford hp d60. Has a narrow spring pad width, which helps with turning radius. And able to locate the shackle hangers in board of the frame enough so you run a lower lift heigth. Also the differential is more centered. And not have to worry as much about hitting the steering box or pitman arm.