So I have a 98 3.8 and have a 5.0 to put in it and I couldn't find anything about what to do with the harness. I don't want to completely replace it, but I doubt it will work with the new motor. I have the ECU that came with the 5.0. Most if not all of the wiring is there on the car.
Okay, so many factors here. The 98 was a one year model car, meaning fuel pump upgrades are a 98 only deal along with many other things. If you are set on using the 5.0L you have two options.
Option 1:
Swap out everything, all wiring, K-member, Fuel System, everything from a 94/95 GT/Cobra
Option 2:
Swap out a lot of the wiring for a 98 GT wiring. You still need to swap the K-Member. Then you'd need to modify the wiring to work with a 5.0L Explorer setup. That setup was OBD2, so has all the "needed" sensors to work. This way you could use the Mustang GT (4.6L) Computer.
Now those are high level overviews but should give you an idea. Not saying its impossible to do, but will require a lot of work. I have done them many times.
ya the car has nothing, got it as a roller I'm about to change the kmember, then drop the motor, I'm going to change all the gas lines and what not, I was just curious what I need to do as far as the wiring on the different motors, like I said the car now has the stock harness from the 98. So I didn't know if I should do something about wiring before I put the motor in or just drop the motor and see what fits.
The car was a v6, so you can't repurpose the engine harness. Like i've stated above you have two options, there is others you could consider, like going Stand Alone and run a Holley Terminator X. That will save you from re-wiring the whole car.