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  1. #1

    Default 302 EFI to carb (car isn't EFI)

    So I can't seem to find the answer to my question, every thread so far to me seems to be converting a car that is EFI over to carb.

    I have an 80 4 cyl, and since the weather is starting to get nicer I want to swap it over to a V8. My question is, if the car is already a carb, can I just throw a carb intake on a newer 87-93 EFI motor and call it a day and will it work? Or is there something else I need to do in order to get it running. I'm trying to find the cheapest and easiest way to get the car to a V8 for now because the way it is isn't unbearable to drive and doesn't inspire safety or confidence.

    Would it just be easier to get an EFI motor and convert mine over? Or is it safer and cheaper just to stick with a carb for now to get the car with a running V8?

    Thanks!

  2. #2

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    Yes you can. The distributor would need to be changed to a 85 5.0 (carb and roller cam gear) and add a timing cover with provisions for a mechanical fuel pump and drive eccentric.

    Mike
    85 GT - owned since 87

  3. #3

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    Pretty much it

    nothing else comes to mind off the top of my head

    i mean you have motor mounts and crossmember and exhaust to contend with. If you want specifics we are happy to deep dive.

    You didnít mention trans or rearend or anything
    Last edited by erratic50; 03-12-2019 at 11:55 PM.

  4. #4

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    Thanks!

    So as long as I find a distributor from an 85 mustang specifically that will work? And I'm assuming I can get a timing cover from any early model 302?.

    So for the rest of the car, my plan was to get a wrecked 87+ fox and just swap everything over as a starting point (motor, trans, rear, etc). I figured it would be much easier to do it that way than to try to piece everything together and have it apart and unable to move. Unfortunately I've never done a job this big before, so I'm not entirely sure how well it's going to work out, but I'm trying to get everything together now so i can make this as painless as possible.

    Thanks again for all the help!

  5. #5

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    Iíve done several engine swaps and thereís benefits to each,

    If you get a donor car you have everything you need so converting to carb means buying more parts.

    Remember that the newest fox mustangs are 26 years old so a lot of parts may need to be replaced on your donor engine.
    Unused a high mile Ď87 donor to build my FFR and had to rebuild or replace almost everything, engine trans and rearend rebuilt, suspension steering and brakes were just used for cores. I may have been ahead to buy a lower mile parts car with useable parts.

    If you go with a carb you can use an electric inline fuel pump and donít have to change the timing cover. This is what I did on my 83.




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  6. #6

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    So as long as I find a distributor from an 85 mustang specifically that will work?
    The 85 Duraspark manual trans distributor is compatible with a roller cam (steel cam gear). I don't think a EFI/auto distributor is Duraspark, its EEC, and it has a cast gear for a flat tappet cam.

    Mike
    85 GT - owned since 87

  7. #7

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    Quote Originally Posted by AldeanFan View Post

    If you get a donor car you have everything you need so converting to carb means buying more parts.
    I know it's more parts, but I'm just trying not to have to deal with wiring up the new ECU to the old stuff. And I know it's going to be old stuff, like I'd probably redo mounts and things like that, but 26 years old is much better than the almost 40 that the car is. I'm going to try to source a carb and find a good distributor to use before I find a car I guess

  8. #8

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    Rock auto had a distributors on clearance right now, hard to beat

    I have a Holley 4010 on one of my cars and it runs great and easy to tune, now sold as the summit carb, good carb at a good price.



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  9. #9

    Default

    You can run a low pressure electric pump eliminating the need to change the timing cover.
    "If you can't explain it simply, you don't understand it well enough."
    Albert Einstein

    1984 20th Anniversary GT350
    Almost "Stock"

  10. #10

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    Thanks so much guys, I'm trying to source all the parts together now. Just more of an opinion question, do you guys like the 2 piece eccentrics or the 1 piece ford racing ones? and do I have to change the timing chain to change that or just the dowel?

  11. #11
    FEP Senior Member
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    If you can find an '87+ v8 donor car, why not just swap it all over and stay EFI? 89+ would give you a Mass Air car instead of the Speed Density. I just finished swapping in a complete '92 donor car into an '80 notchback.

  12. #12

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    Weíre accumulating parts for a swap right now on my dadís Ď83.
    I have a complete Ď89 engine as well as a 4bbl intake and carb.

    The EFI works great and is not too difficult to make work, but requires a high pressure pump

    If I convert to carb I still need to deal with the fuel pump but less electrical.




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  13. #13

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    How hard is it to make all the wiring work? I also know the newer style gas tanks don't fit in the 79-82 mustangs to use an electric fuel pump internally, and I don't really feel like "massaging" the trunk pan to fit since the cars in good shape as it is. Staying carb just seems easier at the moment and I don't have a garage to keep the car in and slowly work on it as I need it.

  14. #14

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    simplest but not the best. just mount a low pressure (3-4 LB) electrical pump in the fuel line near/lower then the tank. One wire ground , one wire to keyed hot.
    "If you can't explain it simply, you don't understand it well enough."
    Albert Einstein

    1984 20th Anniversary GT350
    Almost "Stock"

  15. #15

    Default

    Quote Originally Posted by Airdale View Post
    How hard is it to make all the wiring work? I also know the newer style gas tanks don't fit in the 79-82 mustangs to use an electric fuel pump internally, and I don't really feel like "massaging" the trunk pan to fit since the cars in good shape as it is. Staying carb just seems easier at the moment and I don't have a garage to keep the car in and slowly work on it as I need it.
    Not hard if you can read a wiring diagram. Iíve done it twice and worked well both times, but with Ď87 speed density engines.


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  16. #16

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    Quote Originally Posted by Airdale View Post
    How hard is it to make all the wiring work? I also know the newer style gas tanks don't fit in the 79-82 mustangs to use an electric fuel pump internally, and I don't really feel like "massaging" the trunk pan to fit since the cars in good shape as it is. Staying carb just seems easier at the moment and I don't have a garage to keep the car in and slowly work on it as I need it.
    "Staying carb" IS easier (and cheaper, simpler, more reliable and predictable, and can be tuned to hand fuel injection an embarassing proper whoopin' in the fuel mileage department). All of your points and reasoning make perfect logical sense for your situation. Don't let fuel-injection cheerleaders make you feel you need to defend what you have already decided to do with YOUR 1980 vehicle, lol. I feel it's a shame to turn a vehicle originally equipped with a carburetor into an inefficient, never-reliable-for-long, inside-the-box, always-more-expensive-to-deal-with, robot. For the most part, I think your original question/s have been answered. Good luck with it.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  17. #17

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    Sorry for the probably stupid easy question, but I think I'm going to try to pick up a donor car this weekend, and class has been killing me so I don't have as much time to research this as I'd like.

    Is mounting the external electric fuel pump easier than staying mechanical? What are the pros and cons of it? I'm assuming ease of install (electric) and simplicity and reliability (mechanical)?

    I was looking up how to connect it, but I'm assuming instead of finding a keyed hot wire I can just run a switch to it to manually turn it on and off to save splicing into 40 year old wires?

    Also is there anything I should be looking for? All the crossmembers and mounting points for the rear end/suspension would be the same from a newer car? If this car works out the donor would be a 91 GT with rotted out strut towers.

    Sorry again for the probably super easy and dumb question, but I'm also pretty nervous about doing it since I've never done a job this big by myself.

    Thanks again for all your help!

  18. #18

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    Your engine may or may not have a spot for a mechanical pump.
    If the boss is cast in but not open youíll have to remove the timing cover to mill it out.
    If itís not cast in then you need to change the timing cover.

    For an electric pump Iíd recommend wiring it to constant power through a relay triggered by an oil pressure switch. That way if the engine stalls or in a collision the fuel pump stops.
    Only draw back is youíll have to crank until it builds oil pressure to get fuel so if the carb is dry from sitting it will take a lot more cranking to get it started the first time.

    Wiring the fuel pump is as simple as running wires from the front of the car to the back.


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  19. #19

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    For the fuel pump I think I'm just going to wire it to ignition accessory hot (and also put in a hidden switch to kill it regardless if I have to leave it somewhere) and also nab the inertia switch from the donor car in the unfortunate circumstances of a crash. Should I do the oil pressure switch anyway?

    Okay so, here's another question.

    I have the donor car and I started the swap. So far I've only gotten the rears swapped since the weather hasn't been too kind. However, the ebrake cables were cut and I want to get new ones, but I don't know which one to order. Is it based on the rear end? or did different years route the cables differently? Should I be ordering it for a 91 rear end since that's what it is coming out of? or does it not matter?

  20. #20

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    Iím pretty sure all drum brake parking brake cables are the same in fox body mustangs.




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  21. #21

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    So I don't have enough posts to post in the classifieds yet, and I haven't started a build thread yet, so I'm just posting here (sorry if that's wrong) to say that if anybody needs any 4 cyl parts please let me know as soon as you get the chance, otherwise it might get scrapped. I'm going to keep the things that I think are worth it, but if It doesn't seem like it's useful I'm just going to leave it in the donor car when I drag it to the yard.

  22. #22
    FEP Power Member gmatt's Avatar
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    1,743

    Default

    Quote Originally Posted by Airdale View Post
    For the fuel pump I think I'm just going to wire it to ignition accessory hot (and also put in a hidden switch to kill it regardless if I have to leave it somewhere) and also nab the inertia switch from the donor car in the unfortunate circumstances of a crash. Should I do the oil pressure switch anyway?
    Inertia switch is a good idea in case of accident. Oil pressure switch probably not necessary (in the fuel pump wiring, at least). With a carb, the engine would keep running until the fuel bowls are empty even with no oil pressure and being in an accident doesn't necessarily mean the engine will stop. If you want the engine to shut off with no oil pressure, wire the switch so it cuts off the ignition.

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