Guys,
I also don't know all the differences, but there are a lot between the years. Like on some years, the fuel pump relay is on the pass. side fender and some years it's under the drivers seat. There are difference in plugs for the different years as well. I am with Ray and will only use the same year harness.
As for going carb and what you need... Sorry I can't help on that project. That is probably something Shaun would know, since he converts to carb quite a bit.