1968 Dart gauge help

67Dart273/Del will steer you in the right direction. I had the same issue with fusible link melting. We hadn't even had the car running since buying it. Finished putting car back together and I had an "extra" alternator that we used as the car didn't come with one. Well....smoked the **** outta fusible link, pulled the negative cable off lickity split. Spoke with 67Dart273/Del on the phone and he troubleshot it in 5 minutes. It was bad alternator.
Be sure to check that as well as above advice.