Bought a Mopar found some odd issues.

You can check the ballast resistor with a meter really quick, if you get between .8 or 1.5 ohms I would say it's good unless it's breaking down from heat after it gets warm (I've never seen that yet)There may be resistors with slightly higher values since there are several made for different applications. Mine ohm's out at around .85 ohms. Also double-triple check the firing order. You could also put a timing light on it and watch the numbers on the balancer to see if you have any kind of jumping or erratic timing issues during revving. Did you try a different coil? OOps didn't see that the coil has been replaced.