Hy bens48bigbolt, there are a few things to change when you change ground polarity. If your ammeter was working correctly when the system was positive ground, then you will have to reverse the wiring on the two ammeter terminals if you want to convert to negative ground. You said your coil negative terminal was connected to the distributor, so that doesn't need to be changed when you go to negative ground. The last thing is to polarise the generator before you start the engine, you want to very quickly connect a jumper wire between the armature terminal of the voltage regulator (usually a large gauge brown wire) and the battery terminal of the voltage regulator (usually a large gauge red or black wire), you only need to make a momentary connection to polarise the generator, hope that helps.
