All good suggestions above. I'll just add that the lights dim at low idle by original design. Even in tip top shape the original charging system on 60's/early/mid 70's MOPAR's has the dim at idle syndrome. The OE alternators just do not have a lot of idle output. Many cars lived long lives that way.

Best of the bunch is the latest squareback from the mid 70's. 78 amps rated output and ~50 at idle. It is available reman but reman quality seems variable with 30+ YO cores... the new Powermaster version is a better bet I think.

If you have the 75-80 amp one wire version of the squareback it may help the dim problem and bolt up OK. Suggestions for 1 wire hook-up. 1) Run a heavy wire from alternator output to fender relay. Minimum 8 gauge with either 12 gauge fusible link or 100 amp fuse. 2) tape or remove VR wires. 3) Install a volt meter on a switched 12V source as the ammeter will no longer be functional. 4) Connecting the original charge wire to the alternator is optional... it can help feed the bulkhead connector and supplement the feed from the fender relay but not critical.