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  1. #1

    Default 86 V6 Convertible engine swap

    Hey everybody,
    In my head I want to swap out the 3.8 with CFI for a 5.8 windsor in the future. I cant seem to find anything out there on the interwebs or here in ky limited searching that I have done. The search button is returning an error so I cant go that route at the moment. So I guess that my questions are,

    1) Would it be easier to go carbureted because I have the CFI setup or could I possibly go with EFI if I change out the harness for one from an 87-93 with the 5.0?

    2) Does anybody know somebody or have you done this swap yourself? If so how difficult would it be?

    3) Did the V6 mustangs of this year come with a 7.5 or an 8.8 rear end?

    I know further down the line I will have more questions but for right now this is the ones in the forefront of my mind, as I would like to know if I am wasting my time with something that really wouldn't be worth it. Now I shpuld finish this post up with the fact that this project is by no means in a rush to be completed as it is for my kids and I to do and they are only 9 and 6 at the moment.

    Thanks for any and all hep and information.

  2. #2


    1) HO EFI harness will work - no problem. It's the same firing order.

    Crossover hose for the fuel rails is too short. Ford van or pickup or bronco with a W is a good donor.

    19lb m/he injectors are really too small. They are max duty at 320hp at stock fuel pressure. You will need to tune for the added displacement to get the power out but plenty of guys run 347's with a factory ECU. Adjustable fuel pressure regulator is the usual work around if any is done..... and no 4 CID isn't going to matter in the scheme of things. How the timing is set will matter more.

    They made a 351W base for the "GT40" style upper. 93 Lightnings had it from the factory. It was FMS part too. You could run an Explorer upper with a 351W lower or adapter plates. Personally I'd go Edelbrock or if that's too much money. Typhoon.

    Start with an 86 HO harness and convert it over to MAF when you do the engine harness swap.

    2) several have done v6 to v8 swaps. The thing that will matter about the 351W is the extra stuff needed to make the 351W work in the spot a 5.0L was put as a factory option. Mainly it's flywheel and brackets and headers..... and hood. A cowl hood is needed for a W swap unless you go drop solid mounts and shim the K member where it mounts to the unibody and the hood at the hinges.

    3) 7.5. Only the GT and LX 5.0L got the 8.8.

    sounds like a fun project - good luck!
    Last edited by erratic50; 05-19-2017 at 10:51 PM.

  3. #3


    I'm about to embark shortly on this. What's needed big time, right off the bat, is a 351W Crown Vic or other rear sump oil pan and oil pump pickup.

    No doubt yours will have a 7.5" rear axle in it, just like mine does.

    1) ALWAYS easier, and better, to go with a carburetor.
    1986 Mustang convertible 3.8L ---> BUILD THREAD
    1983 Mercury Cougar 3.8L LS
    1986 Ford Thunderbird 5.0L ELAN
    1966 Ford Fairlane sedan 200-6
    1966 Ford Fairlane GT (390ci 4spd)
    1981 Mercury Marquis Brougham
    1980 Capri RS Turbo
    1971 Mustang Fastback
    1974 Pontiac Luxury LeMans

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