Going to 12 volts on a vintage tractor
When converting to a 12-volt system from a 6-volt system, is the system now a negative ground on the battery? This is on a Ford 8N tractor. I’m not sure if the battery cables are installed on the battery the same as with a 6-volt system or if it’s changed.
An important factor that you don’t address is whether you are converting to an alternator or using a generator. If you use a 12-volt generator then you can maintain the tractor’s original positive ground configuration but if you are changing to an alternator you have to convert to a negative ground system.
Most Ford N-series tractor owners use a readily available kit to convert from 6volts to 12-volts and this kit includes a modern one-wire, integral regulator alternator that requires a negative ground arrangement. This means you have to put the ground cable on the negative side of the battery.
If you put the ground on the positive side of the battery, you will immediately ruin the diodes in the alternator.