Won't start

The grounding stud is behind the tach, welded to the overhead steel cowl. It has maybe 6 or 7 wires attached. The easiest access is from behind the gauge panel. All the power to the ignition goes through the ammeter, and the main ground stud may be implicated, too. Be careful that the 'ignition' light bulb is not pulled out of the tach; it is part of the alternator field circuit. Disconnecting the bulb socket means that the alternator will not charge although it will check out OK. Good luck.