New member, names Bob. I have a 1956 dodge pickup that I transplanted a 1974 subframe, 318 trans, and all the wiring harness 10 years ago.The truck ran fine for several years. MSD ignition box quit working a year ago, bought another off craigslist, it shorted out. Ran the original ignition box for several trouble free months but then the Accel coil quit working. I put a standard coil on and it ran for awhile. The coil I noticed was to hot to touch so I assumed it was ballast resistor. New coil and about a week coil shorted out. As of today I have replaced alternator, regulator, ballast resistor, two aftermarket ignition switches, distributor,ignition control module and 6 different coils all new. Truck starts and runs just fine but after about ten minutes the coil is overheating and shorts out. The battery was changed and the polarity was accidently reversed briefly that caused the first msd box to short out. Plagued with problems ever since. Anyone?

 

Swaps like this are difficult to "remote troubleshoot" because we have no idea what was done to the wiring.

You are running what, the older Mopar ECU? If so, I'd suspect the ballast resistor is wrong or actually bypassed. Is it a 4 or 2 terminal ballast? If it's a 4 terminal, the two resistors are different.

Also, I'd be checking the charging voltage to make sure it's not too high

 

10 years of trouble free driving with the setup. ballast resistor was the first thing I swapped out. Its 4 prong