Things I noticed when doing the 5.0 swap into 4 cyl car
Electronic fuel pump on the Fox body cars is the same for the 4 cyl vs the 8 cyl.
The fuel lines can be easily removed from the 4 cyl, and moved to the 8 cyl. The 4 cyl is on the driver side, while the 8 cyl is on the passenger side.
Headlight/alt wiring is switched 180 degress on the 4 cyl/8cyl. The alt is on the driver side on the 4 cyl
Wiring harness is not bad to change over, I only found one connector that was different. It was the one that is on the driver's side of the car, and does not get swapped out. The one harness is a 3 plug, the other is a 2 plug. The wires are color coded, so just snip the connector off of the v8 and solder it to the 4 cyl harnesss. The wires are color coded, so I guess you don't even need the connector. One of the wires is not used anyway, and this will be easy to fiqure out. It is the one that is not there on the other harness :-)
The fitings for the cruise control/throttle are different, so take the ones off of the v8 car.
Update to post:
I tried to use the old 4 cyl wiring harness for the fusebox, but it would not work. Maybe if it is the same year, but the 4 cyl was a 89 and the 8 cyl was a 90, and there were alot of changes from 89 to 90. I went back to the salvage yard, and got the complete harness, and I do mean complete from the same car that I got the engine. I was having problems with the fuel pump, horn, lights, etc. Now all is ok.
Wow, this has been one heck of a project
"Those who forget the past are condemned to repeat it" Rev. Jim Jones