school me on dash's please

[74slnt6]

ok... well i have a 74 duster, with a old 120 mph dash... i have 4 rebuildable rallye dashs and im gonna have one worked over and replace my 120. I know what to expect price wise ( GULP ) but what about installation? i know the extension pieces will be needed, ( like to extend over the glove compartment) but what can i expect for wiring? will i need a new harness or will my old one work? i know ill need some more wires anyways for the gauges that arent included on the 120's... thanks a lot! I would be lost without fabo ...
:munky2:

 

[res1vw21]

The wiring will work the plugs might not, (I do however remember looking at the late style wiring and the connector looks similar to the rally gauges, but I don't know it if is the same size.) and you will have to get the sensors for the gauges. The wires should be there as there was idiot lights instead of gauges. Compare the wiring diagrams too find proper locations of the wires. Don't forget the rally dash frame is different then the standard frame so you might want to pull the dash and do all the required fab out of the car.