1984 Mustang 351w EFI swap

Bthurbs

Member
Feb 6, 2022
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Hey guys! I wanted to make a post to see how many people have done this swap. I am currently about to start with the wiring harness and could use a little insight into the best way to tackle this. All in all this swap has been super fun but there have been many challenges to figure out along the way. I am planning to make a big post/video of the whole swap as I have found a lot of little things out that could help some more people in the future!

The car I am working with is a 1984 Mustang that had a carburated 302! I found an engine out of a 1988 ford f250 that is a fuel-injected 351W!! ( I know it's crazy )

I ripped out the ECU and the wiring harness out of the truck that I am planning to use in the car. I am hoping I can run the ECU and then use the wiring harness since it was already for that engine. I know ill obviously have to do some splicing to get everything else in the car working, I have been unable to find a good wiring diagram for the car although I found some good ones for the truck.

Any insight into the best way to start this, maybe tips or even if you could help out with a wiring diagram for the car to get things working like gauges. light and whatever else won't be included in that truck harness. Thanks in advance!
 
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Bthurbs

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Feb 6, 2022
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Here are some photos of the car before the swap! It had a 302 with a fast EFI system in it. The last picture is the reason for the 351w swap :p
 

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General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
23,729
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Ouch!!! That engine has an issue with that hole, yes time for an update :nice:
Car looks pretty good, had it long?
Got a cool backstory?? Did it ever out run a camaro?? (Inside joke)
 

Bthurbs

Member
Feb 6, 2022
8
3
13
Ouch!!! That engine has an issue with that hole, yes time for an update :nice:
Car looks pretty good, had it long?
Got a cool backstory?? Did it ever out run a camaro?? (Inside joke)
I don't think I've ever seen a whole that big, there is one on the other side as well! When I bought the car the guy told me it had a " Spun Bearing " but I knew it needed an engine. So far I've only owned this car for about two weeks! I am off work in the winter months so I thought id try flipping some vehicles. I bought a jeep grand Cherokee for $500 and fixed it up and then I ended up trading straight across for this car... I think I did pretty good :D Not much of a backstory but looking forward to writing a few new chapters in the near future!
 

evintho

5 Year Member
Nov 12, 2003
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Sounds like a pretty cool swap! I'm currently dropping a '93 5.0 with factory F.I. into a '54 Ford and I used the '93 ECU and wiring harness. Also had to do a little splicing to marry the two harnesses together. This is what you'll need......
1984 Mustang factory wiring diagram
This is what Ford factory techs used back in the '80s. It covers every circuit and connector in your '84. It's invaluable! Might want to consider this one too............
1988 Ford F150-F350 factory wiring diagram
 

Bthurbs

Member
Feb 6, 2022
8
3
13
Sounds like a pretty cool swap! I'm currently dropping a '93 5.0 with factory F.I. into a '54 Ford and I used the '93 ECU and wiring harness. Also had to do a little splicing to marry the two harnesses together. This is what you'll need......
1984 Mustang factory wiring diagram
This is what Ford factory techs used back in the '80s. It covers every circuit and connector in your '84. It's invaluable! Might want to consider this one too............
1988 Ford F150-F350 factory wiring diagram
Thanks for the links!! Those are exactly what i need. I wish you could buy online versions of this stuff instead of waiting for shipping but.. if it gets the job done then i guess its worth it :D