You now have a hacked up mess. Don't panic, look for your wiring diagram here:
http://www.mymopar.com/wiringdiagrams.htm You will need to look at later Darts to see how the electronic ignition is added to up date the old points system.
Next you will need to start tracing wires to the different gages looking for melting, and bad connections, as well as looking for bad brass connectors at the bulkhead connector (the place where all the wires pass through to the dash on the fire wall). Trace each and every wire one at a time from one end of it to the other. This is the only way to get this car working correctly. It will take a good bit of time
By now you will have discovered most of the short comings in your harness, as well as the wire that connects the gas tank to the dash.
Your dash circuit board may need to be repaired as well. To remove the gage cluster you will need to drop the steering wheel down from the dash,(three bolts at the dash level, and three bolts on the floor flange), and remove several screws holding the cluster face to the dash. After you disconnect the spedo cable (it is hooked to the back if the cluster like a TV cable screws to a TV) the cluster will pull out.
To release the brass connectors from their plastic holders you will need a small 1/16" or less wide screwdriver to insert in it to get the connector to come free of the plastic holder.
You may need to update the fuse holder because of corrosion problems. This is easy to do with a cheep six fuse block and a few 1/4 inch bolts.
My repaired instrument circuit board:
New fuse holder bolted to the existing fuse holder:
replace each bad wire one at a time with the correct color and gage, marking it off the wiring diagram as you go. The diagram will tell you which color & gage wire is used.
New brass connectors can be had from NAPA
Below is my car in March 08', It would not pass current beyond the battery when I got it. But it works nicely now after replacing 30% of the wire, and most of the brass connectors.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC
