I would think when Ign 2 gets power at ballast resister that some voltage flows through ballast to Ign 1 voltage regulator terminal and then to alternator field circuit during Start? Would that reduce volts to coil?
It should not if the wiring is up to it but this IS a source of voltage drop because of the bulkhead connector, quite often.
I am running out of ideas. I really have to lean towards finding a local guy who can take a fresh pair of eyes at the problem.
The same idea is true in "run" and I have posted this many times. The VR power connection IS the voltage sensing. Many old (??most??) Mopars have a voltage drop issue in the "run" position. In a stock wiring car, this can come from the ammeter circuit, the bulkhead connector, the ammeter itself, or drop in the ignition switch, switch connector, bulkhead connector and you end up with drop at the VR/ ballast junction. This drop causes the VR to ramp up and overcharge, AKA the reading at the VR/ ballast junction with IGN1 will read "fine" (14V) when running / charging but the battery will be HIGH.
Once again, I am starting to go round and round. Wish I was there. Bet we could find it