I have a 89 w100 that I recently purchased. It had a 318 in it. The previous owner pulled the motor and left the wiring harness hanging. I'm looking at putting in and older model 360 in the truck but need some guidance in converting the truck from the efi and such to a straight carb motor and ignition system. Would like some help with what bypassing I'm going to have to do to accomplish this task.. Thanks for any info...

 

What I am about to say is for the engine part of the harness only. You may be able to use the wire from the harness as you build your new harness but as the engine harness currently exists it is just about useless. The oil pressure switch and gauge temp sensor wiring are about the only things that will apply to the new install. Just about everything else was controlled by the computer that you are eliminating. Even if you pull the old harness and go with a pre-computer harness you will have to adapt that to the trucks systems. You will need an 89 wiring diagram and a pre-computer diagram to mesh the two systems. Good luck.