Some wiring help needed

[Lippyp]

I put this in the electrical section but got no replies and I was hoping to do this today so I've moved it here.

I have a new M&H engine wiring loom for my 67. It came pre modified for HEI but now I'm having to use a pertronix ignitor conversion in my Mallory as the HEI dizzy don't fit. As a result I have a question. The loom came with a pink and yellow wire crimped to one terminal block which I'm guessing would have gone to the + terminal on the HEI. Does this now go to the + terminal on the coil? I'm guessing as I'm also running a mini starter that the yellow wire is no longer required so when I connect it up can I just tape that out of the way at both ends?

Also, my wiring was so hacked about all I had coming from the original terminal block at the back of the fusebox was two wires, the big purple one and a green one (which I had to trace and unwrap as it then became red and finally blue via two bodged taped connections and ended up at the oil pressure sender! It seems the main pink power feed had been pulled out of the back in the cab and connected to another odd wire that fed out to the coil.

I'm pretty sure I know where the other wires go (purple and yellow to the starter, brown to the brakes, one green to the oil pressure switch) but I have a round connector with a light and dark green wire going to it and I have absolutely no idea where it goes as I don't have one of those! I have attached a picture of it and any (clean!) suggestions welcomed. EDIT: looking at the wiring diagram I think its the connector for the backup light switch on the tranny, am I right?

The other problem I have is how do I get the damn plug out of the fusebox/firewall? I've found a bolt head in the middle but it just spins. Do I have to drop the fusebox off inside the cab to get to the back of this bolt to undo it? I'm guessing I'll need to do that anyway to refit the big fat pink wire into the connector from where the previous owner "re-wired" it. It thankfully does look to be intact so should just push back in.

Damn I hate vehicle wiring, just looking under the dash is scary as theres 43 years of assorted bodges with some stuff seemingly re-wired or bypassed for no apaprent reason like the neutral safety switch that works fine but has been bypassed so it now starts in gear.

The offending extra connector.