Strange things

Best I can guess now the top one is a heater resistor. But the prints for a 74 dart only show the color of one wire. The black one

It hasn't interfered with my asphalt assault yet. Seatbelts are unplugged. But that would suck for it to kick in one day and have me doing the roadside repair

Read up on how it works. Between the shop manual and the Master Tech booklets you should be covered.
For '74 master tech, go to mymopar.com and look for the Master Technicians Service Conference.