Did you consider a Pertronix module that fits in the distributor? I was uncertain but now have 5 years and 20,000+ miles across our 2 cars and have not had one glitch. Best part is nobody's the wiser it is there.
I was running pertronix. But over next to the mopar box. Maybe the wiring to the coil was too long? I had one of those designed to drive brackets but I sold it