73+ Drum to Disc Options

Honestly, for the sake of long term simplicity I would just go to DoctorDiff and buy a 73+ disk brake kit, either 10.95” or 11.75”. Because then all of your parts are off the shelf, OE Mopar parts. Instead of finding an aftermarket kit that uses custom parts or a mixture of parts from other manufacturers/brands/models.

You already have the large ball joint upper control arms, so, you just need the spindle and out and you can get all of that from DoctorDiff.
Dr. diff had a version of his cobra kit that used the A body drum spindle, but discontinued it due to lack of interest. I'm in the same boat, just picked up a set of used 73-up spindles, caliper brackets and proportioning valve. everything else is new from rockauto, and was only about $200 for rotors/pads/calipers/hardware/bearings/seals/hoses.