Hooking up MSD on one of these cars (Cuda/Challenger), isn't all that hard to do...All you need to do is get into the wiring where it went to your old Ballast Resistor and find one wire that's hot when Ignition is in RUN position, and another wire that's hot when in the START position.. Thereare TWO wires in the Ballast resistor wiring that are oriented this way, you just need to find them...After that, it's as simple as hooking up the GM One wire alt. ..
Follow the directions and make SURE you run the BIG RED AND BIG BLACK wire STRAIGHT TO THE BATTERY...I believe the "Purple" wire goes to the "Orange" wire in the stock electronic distributor and the "Green" wire goes to the black wire...