Cruise control was not a option on the 74 Dart, but the 4 pin connector is the type used on cars with cruise. The wire colors don't match any Mopar cruise control from that era. If you really want to investigate further, you will have to pull the steering wheel.
The 3 bulkhead connectors in the engine compartment must be unplugged from the bulkhead.
More difficult to reach if you have power brakes.
Thank you for the responses. I have tried to unplug the connections from in the engine compartment.But they will not disconnect no matter how hard I pull is there squeeze tabs or something holding .thank you