1974 Duster not starting.

YOU MAY HAVE the deadly "seat belt interlock." Whether this is the problem or not you need to bypass it. Find the two yellow // yellow tracer wires in the connector, and splice them together

Here:

http://www.forabodiesonly.com/mopar/showthread.php?p=1969624169

and......

http://www.forabodiesonly.com/mopar/showthread.php?t=14304

HOW THESE WORK

You have two "push on" connectors on the starter relay. These can actually be swapped around electrically. These are the magnetic coil of the relay

One terminal "receives" "start" signal from the key. This comes out of the ignition switch, through the bulkhead IN SERIES WITH the interlock if you have it, and to one of the two 'push on' relay terminals

The remaining relay terminal goes down over the transmission and connects to the three terminal neutral safety / reverse light switch. Connects to the center terminal which goes to ground in park or neutral

HOLD THE KEY in start. Wiggle the shifter from neutral to park. Any click? Try to crank?

Identify the wire going down the firewall from the relay to the NSS switch. Pull that wire off. Ground that relay terminal with a clip lead. Try to crank it

If not, use a light or meter and see if the REMAINING wire is powered with key twisted to start

And......above all else, bypass the seat belt interlock