What are the plymouth dash wiring harness differences from 74 to 75

I am good with wiring. I have both schematics, and a 75 FSM. If only minor differences, we will wire them in or out of the harness. He has harleys and has rewired motorcycles one strand at a time. I have wired cars from scratch, and modded and traced harnesses, and both of us are familiar with schematics and wiring as we both work in the aviation industry. That stuff is all white wires with tracer numbers. I think we will be fine. 1 year apart shouldent be too different that it cant be modded.