Im in the process of rebuilding my 81 f-100 with a 302...and ive been thinking about switching to fuel injection for the fuel economy, easier starting etc. My brother has a 1990 f-250 also with a 302 i could use for parts. What would i have to do to convert? are the two engines compatable? computers...please tell me everything you can. thanks.

 

You would need a computer and wiring harness from the donor motor, along with the intake manifold, injectors ,throttle body, sensors, etc. The big difference is the fuel system, as the EFI system operates at much higher pressure than for the carb. Not saying it can't be done, but it would be alot of work.

 

have done it on a chevy motor, it is not fun but can be done in a day of hard work with a couple of good helpers basically newer heads usually flow better so rip the carbed engine bay down to just the short block and take EVERYTHING from the efi truck

have fun ha

 

I also have a 81 f100. I bought a fuel injected 302, but I just put the carbed parts on it from the old engine, and I have been whanting to change the truck to efi.

For the truck you will need the fuel pumps, from what I have seen the efi pumps from the 302, 351, and 460 will all work, not the 300 I6, it is too powerful. The system uses 2 fuel pumps, one for in the tank, and one for outside of the tank. You may also have to put in an aftermarket fuel tank in order for the pump to fit. You will need the high pressure fuel lines, the computer, and wirring harness.


For the engine you will need the oil pan for the fume ventalation (the vent tube is on the side of the pan).

You will need the exhoust manifolds (for the o2 sensors), if you have a manual trans like I do, you may whant to check and make sure that the exhoust manifolds don't get in the way of the clutch.

You will need the intake manifolds (it is a 2 part system), along with the injector rails, and injectors.

And finnaly you will need the timming cover becouse you most likely have a mechanical fuel pump, and you need to get it out of the system. The timming cover from the efi engine does not have the whole in the side. If you just leave the pump in and disconnect it from the system, it may get in the way, and can be another place gor oil to start leaking, so I recomend putting on the new timming cover while you are doing everything else.

If the engine from the 250 is good and dependable I would recomend taking the whole engine, and anything that is attached to it that your truck does not have (fuel lines, wires, hoses, etc) becouse you are pretty much replacing everything except the long block (block and heads). Do the same thing with the fuel tank(s), find out were the wires go to, and take everything that your truck does not have.

If you decide to go through with the efi thing, let me know how it turns out, becouse my truck is also a 81 f100, it has the long wheelbase with the duel fuel tanks, and I have wanted to do the same thing with it, but I don't have the money or the parts yet.

Good luck!

 

This is just a little tip, don't think of it as one big project, think of it as 2 smaller projects. The first project is getting the engine set up for efi, and the 2nd project is getting the truck set up for efi. As you may have noticed, when I wrote down the parts to be changed, I wrote it as 2 main sections, the parts for the engine, and the parts for the truck. If the truck is set up with efi, then you can put in any of the efi gas v8 engines (302, 351, and 460), you may have to change the computer for each of the, but it will be an easy upgrade if later you decide you want an engine with more power.

 

thanks everyone...thats pretty much what I thought needed to be done except for the timing cover. since my pcv is on my rocker covers, and the hose from my oil fill cap, would i have to get new covers? or just a new cap without the hose? And has anyone else converted to efi here before? did you get a noticable increase in your fuel mileage? thnx.

 

Also, could i drill and thread my own hole in my manifold? my brother has headers on his truck..but there pretty worn out and id rather just stick with the manifold for now.

 

You don't have to get knew valve covers, but my efi 302 had valve covers with an extension for the fill tube, I don't know if it is needed, or if it was just needed on the vehicle that it came out of. But I think you can get away with just using a different oil cap. And atleast on the engine I have the pcv was in the side of the oil pan, but I don't know what year the engine is (I am guessing it is somewhat knew), and the pcv change may have nothing to do with the efi and it may have been ford trying something knew in the 90's, and you may not have to change it.

 

drilling a hole in the manifold for the 02 sensor is probably not a good idea unless you weld a bolt on the outside of the manifold to screw the sensor in to, i would just pick some up from junkyard