The keyed ignition wire should go to one side of a ballast resistor which should have been added when your truck was converted to 12 volt. The other side of the ballast resistor connects to the + side of the coil. The side terminal on the starter also connects to the + side of the coil.
Your coil, even if it is marked 12 volts, is actually 6 volts. The ballast resistor reduces the voltage from 12 to 6 to keep you from burning out your points. The side terminal of the starter connects to the coil so that you have a full 12 volts going to the coil just for starting. When you release the stomp starter, that side terminal disconnects and the coil is powered with the 6 volts from the ballast resistor.
6 volt systems don't need a ballast resistor because, well, they are 6 volts and don't have to be reduced.
There are real 12 volt coils, but you won't (shouldn't) be using one if you are using a points ignition system.
Matt
