Hey mrkiffy,
I just got done doing the 4.0 swap into my 85 BII. You can check out my entire project at this link.
Here is My BII
But here is the thing with my swap. IM CRAZY. Most people try and stick with a 91-94 4.0 because it is easier and less intense. With anything newer than a 94 there is alot more wires. I used a 95 explorer for my donor vehicle.
In my swap i took almost everything from the 95 explorer and put it in my BII.
Heres a small list of what went into the BII From the explorer:
4.0 engine
Complete dash
Complete engine wiring harness and computer
Complete engine bay wiring harness (headlights, horn, etc)
Partial Body wiring harness (less the crap for the electric door acc and keyless entry.
Built in stereo amp.
Firewall (yeah the whole firewall got switched)
HVAC (heat and AC system)
Edie Bauer grey lether seats and center council.
Soon to go in
4r44e from explorer (i was not born with three feet so it is hard to wheel with a standard transmission)
Rear 8.0 from the explorer
Front Dana 35 from a 90 BII
4" lift from a 91-94 explorer
The only thing i left from the BII basically was the Brake booster.
My fuel pump came from a 90 BII with a 4.0.
So if you have any questions im sure i can try to help you answer them.