Re: 69 with battery in trunk, one wire alternator, MSD, nothing else w
The battery is grounded to the frame with the battery cable. The only other ground wire to the battery is the black wire for the MSD.
There are two hot wires from the battery.
One goes directly to a one wire alternator.
One goes inside to the MSD on the kill switch and then has a jumper wire that goes back out to a small junction point on the firewall (outisde) which has multiple hot wires connected that go all over the damn place, including to the starter... That's probably the cause of the problem.
I hate electrical.