69 dart amp gauge

You need to do a couple of things. Go look up the MAD electrical article to find out why, take apart your bulkhead connector and repair it, AS IT IS STILL GOING TO BE USED for power into the car, and INSPECT and then bolt and insulate the two ammeter wires together

Then, instead of the mad article, run some large ga. wire from the alternator stud to the Starter relay "big stud" or better yet, as direct to the batter as you can get.

AND PUT a breaker or fuse in that line. If you don't want to buy expensive wire, run 3 or 4 no 10's in parallel, and depending on how large your alternator is, go from there. I'd use at least no.8