They run great with the OE electronic distributor, but you don't use a ballast with these types of coils.
I have two full different ignitions.
The one on the car right now is a GM 8 pin HEI module with an advance and total timing modified OE Chrysler magnetic pickup distributor and E core HEI coil.
(Same as the HEI kits I used to sell here)
The second is the Ready to Run HEI distributor, a C core coil and 10.2mm Dragon Fire plug wires. (the red ones I posted the pic of above)
I have also run a E and C core coils both with the stock Mopar ECU with a bypassed ballast without any issue's.
