If you want to keep from burning up your points as fast, including times that the key may get left in the on position without the engine running.... use a ballast resistor that is .47ohms on 6 volt. This doesn't drop the voltage as much as provide a load in case the ignition gets left on. I have seen this nice feature on 6 volt cars and trucks before. 12 volt ballast resistors are usually rated somewhere between 1 to 1.5 ohms.
