MSD brain teaser

If you are referring to the ones in the car harness, they originally went direct to the Mopar ECU. Not used.

WHAT I "would do"

Get out the original destructions for the MSD distributor and wire it up as simply as possible, IE do not use the car harness AT ALL. Hook a clip lead to get your 12V and get that much working.

Then if you want to use the MSD box wire it up the same way, that is "hot wire" with clip leads.

MAKE SURE there is nothing else hooked to the coil. No capacitor, no tach

"The thing" about the original ballast and factory wiring.

The "ignition run" wire comes from the ignition switch, through the bulkhead, and splits off somewhere to feed "other stuff." It feeds the ignition resistor, the voltage regulator, alternator field (blue) and some smog doo dads in some cases.

THAT WIRE, the ignition "run" or "IGN 1" goes COLD when starting.

SO HOW do you get spark in "starting?"

There is a SEPARATE wire, usually brown, which originally was the "coil resistor bypass" or IGN2. This ALSO came from the switch, through the bulkhead, and IS THE ONLY power that is "hot" for ignition during "crank."

This originally fed direct to coil + by hooking to the coil resistor. If, somehow, you did not get that connected, you won't have power in "start."

So you need to check that. Use a meter, and see if you have 12V both in "run" and in "start"