I remember those. If it went bad the engine would start, but die as soon as you disengaged the starter. The ignition coil was actually for a 6V system, and the ballast resistor dropped the voltage to the coil so you didn’t burn it up. There was a second wire off the starter circuit that bypassed the resistor and gave it the full 12V to insure you got a good spark while it was starting.
And then there’s that unique starter sound that Mopar’s had in that era.
“There was a second wire off the starter circuit that bypassed the resistor and gave it the full 12V to insure you got a good spark while it was starting.”
Actually the reason the ballast was bypassed during starting was to apply full battery voltage - but since this was during starting, that voltage was much less than 12 Volts...so the voltage to the points was about the same whether starting or running (i.e., with the ballast in line).