The coil voltage needs to match the battery. By using the 6 volt coil on 12, even with a resistor, you're roasting the points. Change out the points and condenser, get a "12 volt" coil that requires a resistor, and wire things up according to a 55-up wiring diagram with the resistor in the circuit from the ignition switch to the coil. Use a bypass wire from the starter solenoid "S" terminal to the + side of the coil if you 're running a key-type start, or a 55-62 year stomp starter switch with an extra terminal for resistor bypass if you're using a 6 cylinder engine with a stomp starter.
Jerry
