Classic/Antique Car Repair: Plymouth Valiant Wont Start, ballast resistor, plymouth valiant

Question
Got a 1972 Valiant with a slant six that won't start.
When the ignition key is cranked all the way, the engine starts but shuts down when I relese the key to the RUN position.

Thanks,   Ray

Answer
There is a white resistor block attached to the fire wall near the back of the engine. this is the ballast resistor for the ignition. It is most likely blown. When turning the key to the start side the resistor is by passed but the electricity is transferred to it in the run position.