It's really worth investing a few evenings looking at your car and learning how to read the wiring diagrams. I always find it seems impossible to understand at first, but then after a bit of looking and prodding Things start to make sense.

As an outline, leave all wiring in the car that doesn't connect to the engine. That's headlights, blinkers, horn, and all stuff like that. From memory there are only a handful of wires that connect from the car to a 4AC. Most of them are in the plug you pictured (reverse light, temp sensor for dash gauge, starter signal, etc). There's also the alternator as Dogan has mentioned (this is slightly trickier as the 4AC alt is externally regulated while the GE one has an internal reg) and a wire or two to the carb. So sorting these few wires out isn't hard.

Then there's the wires needed to run the engine. I'd recommend connecting the loom up to the engine and peeling the cover off everything. Then by looking at it with the wiring diagram you can Work out what every wire does and removed the irrelevant stuff. You can also find out what connections you need from the car (mainly +12V and earth). Then extend/trim the wires to length and make a neat loom. Then start her up and enjoy... or that's the plan.

I'm not far from Bendigo so could possibly come past some evening, but am away for the next couple of weeks. Drop me a line if you're still scratching your head at the end of August.
Hen