Here it is, I have an '87 F150 xlt lariat, 4x4 4 speed, 3:10 gears it has a dying 300I6, the top end is going, and the wiring harness is destroyed. I have a donor truck with a 302 of the same year. I need to know details regarding wiring and the computer, the motor mounts and radiator etc I can handle.

 

Easiest is get a donor wiring harness from a truck that also has an I6 / manual transmission and it'll work. Far as I know 4 sp and 5 sp should be the same. It'll also have to be a harness from a MAP truck, not an MAF truck. Other than that shouldn't be any issues.

I would imagine the harness is largely the same; the sensors are the same and the injector harness can be changed to one for a 6-cyl... Someone here probably knows if they're the same or not but you could always may them out next to each other and make sure for yourself. You'll need a 6cyl computer for the 6cyl engine though, I'm sure of that.

 

I'm goin from the I6 to a 302, would it make a difference if the donor truck is an auto tranny?

 

I'm not sure. Some transmissions dont have any electrical interaction with the computer. The C6 (3 speed non-OD) operates with just a vacuum connection and a kickdown cable where as the E4OD I've heard has some kind of connector to the computer. I think a C6 and 5-speed could probably use the same computers... but that's just speculation. Worst case scenario you may have to get a computer that matches the 302 and trans you have. The wiring harness on the donor motor will work regardless.

 

i remember my first time





engine swap

 

Change the underhood engine harness, change the computer. Easy stuff. No issues with the tranny, '87 isn't computer controlled.