Harness compatibility help

So I recently bought a full body harness that was for a 1974 duster and I wanna use it in place of my butchered 1973 duster wiring harness. I believe the dash harness is compatible because it looks extremely similar to the harness that’s already in the car. My problem comes when I was comparing the engine bay harnesses. Looks to be a noticiable difference. I understand it’s a different year harness for a different car and it should be different. I just wanna know if there is specific things I should be looking out for, if anyone who has done this before can help it would be appreciated. I’ve never done a harness before and I’m trying to do everything right the first time.

1973 duster, automatic with 360 la small block, I don’t know if having this matters or not.
Idk what the 1974 duster was