I don't know about a 63, but i had a 71 duster 318, that done the same, it was my Neutral safety switch, if you have a relay and know the contact that goes to nss, put a wire under the a bolt on motor and a connector on end of wire and put it on relay where nss is, if its a bad switch, be careful , when relay has ground attached ,it will start in any gear as well as park and neutral
What color is the wire that goes to the relay i had 2 wire one was a pink looking and the other was black or dark blue and i just guessed on where they went could i have the wrong one plug to the relay i plug the other one to the horn relay.
