Resistor drops the 12VDC to the coil to about 9 VDC so the load the points switch on and off isn't as great...makes the points last longer. With any MSD that I have worked with there is no resistor used as the two wires from the MSD box go DIRECTLY to-from the coil, and no other wires are wanted on these lines as they are 200+volts.

As I recall, each of the different electronic boxes from Mopar have a recommended resistance value. I think I have a .25 ohm on my Chrome and Orange boxes. Better check with the install instructions or someone else here.

BTW, you can't get a .25 ohm in stock resistors, and there is quite a variance in over the counter resistors.