Flicker flutter
Just rereading what you first posted to see what I may have missed or misread.
There is connection to the voltage regulator at one of the ballast resistor terminals. That was just a convenient location for the factory to make a junction. The alternator and regulator do not use the ballast resistor.
The ammeter will only indirectly a voltage regulation problem.
Just rereading what you first posted to see what I may have missed or misread.
The ballast resistor is for the ignition. It lowers the voltage so the coil doesn't draw too much and also helps protect the distributor's points. For a points system it should be somehting like a 0.7 Ohm resistor and for a Chrysler electronic system it should be 0.5 Ohms.
There is connection to the voltage regulator at one of the ballast resistor terminals. That was just a convenient location for the factory to make a junction. The alternator and regulator do not use the ballast resistor.
Not sure but this is why I suggested observing alternator output voltage with rpm.
The ammeter will only indirectly a voltage regulation problem.
