I have a 1967 Dodge Coronet R/T, 440 motor with a mild cam, 2 fours, 2-1/2 inch headers and 727 trans. The ignition system was changed to a Chrysler electronic system years ago. Several months ago, when I tried to start the motor, it would crank but not start. It was not getting fire to the plugs. When I turned the ignition switch completely off, the motor would ‘jump’ and act like it would backfire (it did a couple of times). Eventually it would start, after I pulled off and put back on the coil wire between the coil and distributor cap.
I have since changed the ignition switch, ballast resistor, and control module. But I still have the same problem except now it won’t start at all. What could be the problem and how do I solve this, short of putting on a $900 MSD, or the like, ignition system?

Thanks for your help.