75 Duster electrical boxes

Many times, these are emission related. I've seen distributor spark delay boxes, choke delay, EGR control...
Wait until you look under the dash. In 1974, FEDERALLY mandated seat belt interlocks were installed! If the seat belt was not connected, the car would not even spin the starter. If you had even 25 lbs sitting on the passenger front seat with the seat belt loose, the car would NOT start. Under the dash was a blue plastic control box, inside was a mini computer type circuit board. All sorts of wires ran in and out of it. In the engine compartment next to the spark ECU was a reset box for the system.
What a POS.