Ampmeter wiring

I was at a cruise on Friday, just north of Pittsburgh Pa. ther were over 3000 cars and over 8000 people there. AMAZING!!! Anyhow , I was talking to the guy parked next to me. He had a 1968 Satellite. I was telling him how my 69 Dart went ( up in smoke). He told me that it was probably the ampmeter gauge wiring. He said that all of the voltage in the car runs through this wire and it can get hot and start a fire. Is this true and if it is how can this be fixed? He mentioned something about a fusible link. My other 69 Dart is overcharging a bit and I was wondering if this could be the same problem? Thanks!!!