Unless something has changed from when I bought and installed the conversion kit many years ago, here's what I can tell you. Since the the"orange Box" Mopar kit replaces the points distributor, it was intended to use a "stock coil" and "stock ballast resistor" same as the points system and would have been original to the car. The function of the ballast is to be a current limiter for the coil which helped extend the life of the points which were subjected arcing as the coil is initially energized. The condenser associated with the coil kept the sparking of the points from causing static and interference with the cars AM radio.
In the Mopar "Orange Box" system, the switching action of the points is a power transistor that doing the switching on-off of the coil. The reluctor in the distributor magnetically creates electrical pulses to feed the orange box electronics that among other things controls the on-off cycling of the power transistor.. I run with a stock coil and stock resistor. The orange box that came with the Mopar kit I bought from Mancini did fail after about 2 years of operation after I did the conversion. A replacment orange box still going strong after some 10 years now. I had used the Mopar distributor for a year or so and found that it produced mixed results and was never very happy with the physical quality of it, timing did not remain stable IMO. I upgraded to the FireCore distributor that I've had for about 12 years with no issues, runs perfect and timing remains rock stable, so that was a good choice. I do however carry a spare coil, spare ballast resistor and spare orange box, and multi-meter just in case.. I try to keep my 66 Charger as original as is reasonable, so still run with stock coil and ballast resistor with no isssues. Of various brand coils, some want a ballast resistor and some say it's not required. Perhaps you may want to consider the stock coil and resistor My opinion, sure some may disagree..
