I have never used a ballast with any electronic ignition and aftermarket coil. My local speed shop has been building mopars for over 35 years. He never uses a ballast resistor with electronic ignition. I use the blue HP voltage regulator, constant 13.5 volts.. I've never had a problem. Car has never skipped a beat. Just check your coil. MSD blaster says in there paper work not to mount it lying down, as a stock mopar would. If i'm going for a stock look i use MP coil.