Well... it seems that I threw a rod in my 1994 5.0. Block is trashed and other parts were damaged. I have a 5.8 windsor on the line. I am pretty sure that the transmission will mount up correctly because the bell housing pattern should be the same, I know that I will need a new flywheel for the 5.8. I know that I may need a larger down pipe as well Which I believe I can pic up from a junkyard for cheap, or even cut off and use clamps. If I use the distributor and all the pulley driven components from the donor vehicle will I have any other problems? I really need to get this truck in running condition (my lease is ending soon). What other differences should I be aware of? fuel lines? computer modules? distributor? Will I need an entirely new pressure plate and clutch or should my current ones work? The 5.8 is a 1991 by the way.

 

I think the distributor is different. The length is near the same probably, but there is something that's been listed as incompatible for such a long time I don't remember what it was.
But the gear itself would need to be changed if nothing else. Your '94 5.0 should have a roller cam(?) but the '91 5.8 still had a flat-tappet cam. So the gear material is different.

Obviously all the intake stuff needs to be 5.8, and the harmonic damper needs to be for the 5.8 as well. Presumably you have that part still installed on the engine, but if not it has to be the 28oz imbalance that the 351W's have always had. Just like the flywheel.
Even though the exhaust manifolds will bolt on from each one, I'm not sure if there were any actual differences other than the down tube length. Because the 5.8 is taller, something will have to be done to raise up the manifolds unless the 5.8 manifolds have a longer "collector" area? Not sure how that was handled by Ford.

Is the existing 5.0 a Mass Air Flow engine? I think so, and your 5.8 would be Speed Density.
If you keep your existing PCM I think you have to convert your new engine to MAF then.
Either way though, you will have to adapt the harness one way or the other. Either using the existing one and plumbing your engine with all the correct sensors and stuff, or keeping it SD and swapping out your harness and computer for the one that came with the 5.8.

Probably a million other tiny things that are not deal-breakers, but make certain that it's not a perfect plug-n-pay and that you have to plan for three different ways!

Paul

 

Thanks for the detailed response, that is why I love this forum. To clarify I am basically going to take a running engine out of a junker car, the bronco runs and drives well but my friends bought it to part it out... Basically drop it straight into my truck. I am not worried about having it be perfect I am mostly worried about things that would cause the truck to not run at all. Sounds like I may need the new PCM. Could I grab that out of the donor vehicle and plug it into mine? would that be ok to do even from a bronco to an f150?

 

Yes, I don't see any reason that would cause a problem. In fact I'd get the donor ECU no matter what. That way it will match all the sensors expectations and such for the best running.
I'm sure they are "different" in their one function or another, but I can't see them having any incompatibility concerns with the vehicle itself. I mean, most of the functions are strictly engine control anyway. So it's not like having no more back window, or 2wd vs 4wd (if that's a change too?) is going to cause it to not run right.
Then again, I've been wrong about this electronic stuff before!

I'd want to hear from others about any changes in security functions between '91 and '94, if any, before assuming everything will be perfect.
But I don't know of any pitfalls myself. Might not even need a new flywheel after all. If both engines are running the same type of trans, then the one that comes with the 351 will be correct already. Both should have the same 164t ring gear and the right offset. If one had an AOD for example though, and the other an E40OD then maybe there is a change needed?

Interested in what others say as always.

Paul

 

dont forget the TFI/ICM is distributor mounted on the 91(351w), and is remote mounted on the 94(302), 2 different start systems, what trans? Is your truck MAF, or SD

 

The 351 distributor is longer/ taller then the 302 distributor. From what I understand wouldn’t use any of the wiring from the donor engine.