new ballast resistor died in 10 minutes

Since it is a 4 pin, did you observe the orientation of the resistor? The resistance in the 2 halves is different. There is a nub or gap in the back that should only allow it to mount one way. If the high resistance half was accidentally put in series with the coil (instead of in series with one of the wires to the ECU module), then that half would get too hot.

For 1972, do you have a Mopar ECU and distributor? I ask since you put in a 4 pin ballast.