Ok. Things youll need.
Easy access to wiring diagrams
Aftermarket fusebox and relay box. You can get them at AutoZone for $20 each.
Spare wiring of varying colors and gauges.
Soldering iron, solder, and knowledge of how to solder.
Self tapping screws and washers
Four feet of 4 gauge wire
And a lot of patience.
Here we go. Full thread hijack at this point boys.
This is what I am using as my example. It is a 1990 SC with an explorer 5.0, paired to an m5r2. It was built as a drift missile, so everything done was just to make it run and that was good enough.
Leave your factory starter relay inplace, but add a 4 gauge wire to the run side. Same side the factory body harness is connected to.
Run that wire to your added fusebox. I used the factory 96 explorer box, but a fusebox is a fusebox.
This will house your fuel pump fuse, eec main fuse, o2 heater fuse, eec memory fuse, and ignition coil power fuse. The eec memory fuse will also be used to keep power to the OBD2 port.
The relays control the fuel pump, eec, o2 heater, and ignition coil power. You can also add a relay for your fan, since the Tbirds EEC has a signal wire to kick that on.
Get your self one of these wire brackets(?), off a 96 or 97, to protect the harness as from getting cut or shorting to the body. You can also see where I added my EEC ground on the right.
These are the signal wires coming from the EEC and engine harness for rpm, oil pressure, coolant temp, speed, obd port, ect. I honestly dont remember every wire as I did this swap in the summer of 2019 within a 3 weeks period. Fun fact, I put on 25lbs during this build.
Here is the wiring popping through to the driver side, under the dash and then up to the instrument panel. That was the easiest was I found to cross them over.
And thats that! I will not get into which wire goes where or does what because an explorer harness is different from a birds. But the swap you are planning is similar enough to mine to where this, imo, will probably be helpful.