I'm swapping the seized 5.8 in my '90 F250 out, and putting in a good '92 F150 5.0. I noticed that the distributor plugs are very different. The '90 5.8 has a distributor mounted ICM, the '92 5.0 has the ICM located on the fender apron. I wanted to use my '90 F250 wiring.

Should I go get an 87-91 5.0 distributor?

Will it work on the '92 5.0?

Does the 87-91 5.0 have distributor mounted ICM?

Are there any other differences between these wiring harnesses?

 

Yes you need an earlier 5.0 distributor with the TFI module mounted on it. First check to see if the motor has a roller cam or not.. it should but make sure by looking for a dogbone around the lifter...should be able to see that if you remove a valve cover and shine a light down the pushrod hole. If you do see a dogbone then you need a distributor with a steel drive gear, one from a car 5.0 will work since they have all had roller cams since the late '80's, or you could use an '87-91 truck distributor but you will have to pull the drive gear off the '92 truck distributor and mount it on the replacement, because all the early truck motors had flat tappet cams with cast drive gears.

 

How tough is it to pull the drive gear and swap it? I can get a distributor for free from an '89 truck.

 

The gear isn't that hard to remove but it does require a puller, reinstalling it can be done with deep sockets and hammer. Also make sure you get a 5.0 distributor because the 5.8 version won't fit in the block... if you have not discovered this already.