No power on “cranking” cycle from key-73 Dart

By jumping across the terminals you’ve verified the power from the battery to the solenoid is good if it cranks. Check for voltage on control wire at solenoid terminal, should be yellow wire. Clean mounting area and solenoid mount, that’s where it grounds. This is where I’d start. If there’s not voltage on control wire at solenoid then you’ll need to start back tracking through the neutral safety system to the ignition switch to see where power is lost. Have you tried starting in neutral? Also may want to go to Service Manuals – MyMopar to download service manuals for your car.

Sorry was not fully awake when I posted. Corrected my error.