Classic/Antique Car Repair: Battery 33 pontiac, ammeter, alternator

Question
Is my 33 pontiac with straight a positive or negative ground. I have heard both. Having problems with gauges.

Thanks

Len

Answer
As far as I know it is neg ground. The best way to tell is to hook up the battery with neg ground and turn on the headlights. If it is correct the ammeter will show a discharge. If it shows a charge it is wrong. Do not try this on a vehicle equipped with an alternator, only a generator.
Brad