At wits end......

Proform mopar electronic ignition box,
ballast, distrib. With msd blaster coil.

I myself don't believe a fuel issue.

Original voltage regulator but charges
alternator fine?

Got to be electrical under load.......
gonna swith ballast, coil, cap rotor

Have you used the dizzy before? If not I would check rotor phasing, maybe throwing spark between 2 terminals. Also double check tdc and make sure your marks line up on the damper, if damper slipped timing is off and can cause it miss