Beyond Frustrated - Wont start/stay running

Have you examined the points to see if the points are clean and flat or if there is a 'tit' of material on one side? I think you checked dwell, but you should also check the points gap with a feeler gauge when the points are at their maximum opening; they should be open around .018-.022".

Can I make a suggestion to check your spark without a spark tester? Make one yourself. Pull the spark wire coming from the coil from the center post on the distributor cap, and place the open metal end about 1/4" to 3/8" from metal (valve cover or fender). Crank and watch the spark; it ought to be a bright blue, not a weak yellow. If you get the bright blue spark, then you know that your coil, condensor, and most of the wiring is OK. This does not check the ballast, however.

Also, what do you have for a ballast resistor? There are many types of ballast and most are wrong for the Mopar system. The only ones worth using are the MSD that is 0.8 ohms cold, and the BWD RU19. If you have an ohmmeter, measure the ballast resistor cold; place the meter leads together first and note the resistance of the leads by themselves, and then measure the ballast with one end disconnected from the car. If it is much more than 1 ohm cold, then get one like listed above. The original was 0.5-0.6 ohms cold.

Also, your coil primary resistance should be around 1.5 ohms. There are some 3 ohm coils out there and they are wrong for a system with a ballast in them. You can measure this across the + and - terminals of the coil with them disconnected from the car.

And if you do have that ohmmeter, there are some other checks to run but I don't know of you even have an ohmmeter. A decent volt-ohmmeter will pay for itself fast when troubleshooting this vintage of car.