I haven't driven my '64 Dodge in over 7 years, and spent the last several weekends getting it back in shape: new gas, oil, brake fluid, etc. I got it all working, drove the kids around the neighborhood and washed it. When I went to start it to put it in its parking spot, all the magic smoke escaped from under the hood.
The dark blue wire that runs from the ballast resistor to the voltage regulator burned in two, and the dark blue wire that runs from that same ballast resistor connector back to the bulkhead connector melted the insulation and took out most of the other wiring insulation in that bundle. The story I told myself was that the 50+ year old wire had corroded at the voltage regulator connector, broke and touched the firewall, which grounded that circuit and melted the insulation.
I rebuilt that wiring harness with new wires, with the right terminals and crimpers, and wire gauges called for in the FSM. That same circuit melted its insulation again when I tried to start the car. I also checked under the dash; that same circuit runs to the IGN1 terminal of the keyswitch, and it's melted, too.