Drums to disc brake help

Aftermarket ( Doctor Differential maybe ? ) has a taper bushing to poke in the 73 model spindle hole that makes the earlier smaller ball joint stem fit it. I haven't used these pieces, just see other owners have. Seen no negative feedback. So that's positive,,, right? The only drawback is, The aftermarket kits that contain 4 ball joints for this model or that model would be wrong for this mixed makeup. You'll need to piece mill the rebuild, upper ball joints correct for the car, lower ball joints correct for the spindles.
I would screw the upper ball joints out of the arms before buying anything. If those threads fail you'll need upper arms anyway. Chit happens. Good luck