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  1. #1

    Default 1985 CFI to carb swap inbfo needed.

    I was wondering if it is possible to install a Holley 4412 two barrel carb on the stock '85 Mustang 302 CFI intake manifold?

    The base of the carb and CFI look to be VERY similar although I haven't removed the CFI yet. I wanted to find out if the swap was possible first, plus I need to measure things up to be sure that the TV cable mounts to the carb in the same position as it does to the CFI. I guess that these are very sensitive to positioning and adjustment in order to work correctly and not ruin the AOD.

    Reason for the swap is that the CFI isn't working at all and the "brain" is toast. I like the simplicity (performance will suffer, I know) of the little Holley two barrel, I have one rebuilt on the shelf, I'm pretty cheap and would rather not have to invest in an aftermarket intake and four barrel, and if it can be swapped over, it'll enable me to keep the convert running through the Summer, the perfect time of year for an '85 convertible GT !

    I've looked everywhere on the net for some pics of the CFI and stock intake but found nothing of use, so I'm asking here.

    Thanks for any info !

    T

  2. #2
    FEP Power Member grtskydog's Avatar
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    Pretty sure the CFI intake is just a 2bbl standard flange. There is an EGR passage you'll need to block or re-use the spacer.


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    Ed

    "The Dude abides."

  3. #3

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    The bolt patterns of Ford 2-bbl CFI and Holley 2-bbl (as well as Autolite/Motorcraft 2-bbl) are identical.

    If you begin reading at post #76 in my build thread (link in red below), I tried to document well a way to go about doing this. Yes, mine's a 3.8 (with a LIST-4412-2 500cfm 2-bbl), but there's no difference above the carburetor mounting flange. Within my thread are also some fuel pump/regulation and ignition ideas. You can buy or make the bracket for attachment onto the throttle lever, that must be adjusted right at idle and pull the cable at a 1:1 ratio for AOD.

    Simplicity? Check.
    Performance suffering? I wouldn't say so.

    Good luck with it.
    Last edited by Walking-Tall; 05-07-2017 at 11:03 AM.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1966 Ford Fairlane sedan
    1966 Ford Fairlane GT
    1981 Mercury Marquis Brougham
    1980 Capri RS Turbo
    1971 Mustang
    1974 Pontiac LeMans

  4. #4

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    Thank you VERY much guys ! !

    Great forum, so much knowledge and SO freely given ! ! !

    Another "problem" solved . . .

  5. #5

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    A few friendly suggestions for using a LIST-4412 500cfm Holley 2-barrel (the exact equivalent of the front half of a 750/780 LIST-3310 4-barrel) on a stock/stock-ish, non-racing engine and vehicle.

    There are ~0.025" bleed holes in the main body's throttle bores, about 1/4" directly above where the transfer slots are in the throttle base plate, that encourage early and notoriously rich idle and low-speed transition characteristics. If you find those conditions, and/or "fun" to adjust idle mixture screws and "fun" to calibrate IFRs/IABs (whose factory size, the IFRs, at 0.036", is more suitable for long duration camshaft use in 1-11/16" throttle bore Holley carburetors. 0.031" IFRs would be a better place to start. The factory 0.068" IABs should be an okay place to start as well) if you're into that, you'd do well to block the bleeds with epoxy. Not the transfer slot passages in the body, but just the bleeds from those passages that go into the bores above the throttle plates.




    Ditto (block with epoxy, jb-weld, other, etc.) with the holes in the throttle plates, where the extra idle airflow just is usually not necessary with something stock, cause a too-high idle speed with the idle speed screw backed right off, and/or completely close off the transfer slots at your idle speed setting.




    IMHO, the 50cc accelerator pumps only belong on the "REO" trucks they were designed for, LOL! 30cc, totally adequate.
    Last edited by Walking-Tall; 07-19-2017 at 10:16 PM.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1966 Ford Fairlane sedan
    1966 Ford Fairlane GT
    1981 Mercury Marquis Brougham
    1980 Capri RS Turbo
    1971 Mustang
    1974 Pontiac LeMans

  6. #6

    Default

    Sounds like really good advice. Wonder why those tiny holes are there anyway, seems like they would result in an excess in emissions as well as an increased idle speed. Certainly something that Ford would want to avoid.

    As the 500 Holley seems to be a truck/van carb, would I be better off using the little two barrel that came off of my Capri V6 engine? It's a Motorcraft 2150 approx. 300
    cfm.



  7. #7

    Default

    Addressing the issues outlined and shown above has made a Holley 500cfm LIST-4412-2 work very well on my 3.8L V6. Not addressing those issues with a stock/mild install would make things stupid-rich, pretty much everywhere in it's function.

    Much more than a truck/van carburetor, they have been (and are) predominantly used for racing where a two-barrel carburetor is required, and that's why all of the richer calibration right out of the box. You'd be fine (it should work very well) using one on a stock 302, IF you address those issues... because they aren't necessary or appropriate at all for something stock or mild. IMHO, no, not better off, the bores and venturi are probably quite small in that Motorcraft... now, there are bigger Autolite/Motorcraft carburetors. A small block Ford spec two-barrel normally has a 1.08 (1.08" venturi diameter) cast on the front driver's side... they were made as small as ~less than an inch size venturi, all the way up to 1.33" venturi size...
    Last edited by Walking-Tall; 05-25-2017 at 04:00 PM.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1966 Ford Fairlane sedan
    1966 Ford Fairlane GT
    1981 Mercury Marquis Brougham
    1980 Capri RS Turbo
    1971 Mustang
    1974 Pontiac LeMans

  8. #8

    Default

    OK then !

    Other than this two tiny holes indicated by the arrows in your photo and the holes in each "butterfly,: is there anything else that I ought to do with the carb before trying it out.

    I rebuilt it last year and it's been on the shelf ever since. Not sure which accelerator pump came in the kit, but I search for the one that you recommend.

    Otherwise, all set with those mods?

    We used to put a rivet in the hole in the "butterfly" on all of the Solex and Webber carbs that we used on the 356, 914 and Ghias. Worked well or not, it was always a mystery. Sometimes great, sometimes horrid.

    I was sort of aware of the two barrel being used in racing applications where required, would you know what the carb was original equipment on other than the Ford van and school bus? Any pick up trucks or passenger cars? My buddy's father had one on his 351 powered work van way back when . . .

    Thanks for the advice !

  9. #9

    Default

    Disabling the transfer slot bleeds (with epoxy or sleeving the passage behind it with brass tubing to block them) and the idle air bypass holes in the throttle plates (epoxy or rivets securely or something) are a good start for decent stock mild street function. The factory 0.036" IFRs (idle feed restrictions) in LIST-4412's are better suited for something with a very long duration camshaft. For it, and for other Holley carburetors that have 1-11/16" throttle bores, 0.031" PIFRs (primary idle feed restrictions) is a better place to start with something stock or mild for the street.

    IFRs - numbers 8 & 20:






    Thing is, you can dial out idle circuit richness with the idle mixture screws, FOR IDLE, but IFRs that are too big can/will negatively affect off-idle/low-speed/cruise economy, fuel mileage. So, for a baseline (because I drill and tap these passages all the time), I would start with 0.031" IFRs with drilled and tapped for 6-32x1/8" brass socket set screws (or you can insert fine (~0.018") wire bent in a V, sticking into them and into the angled passages beside them that go into the main wells (8 & 9, and 20 & 21), that will reduce the area of a 0.036" restriction down that of a 0.031" restriction)... *

    * The math: 0.036" (0.00102 square inches) - 0.018" (0.00025 square inches) = 0.00077 square inches, or ~0.031" (0.00076 square inches)

    ... and I'd possibly/probably end up increasing the ~0.068" primary idle air bleeds with drilled and tapped for 8-32 or 10-32 brass socket set screws, to maximize off-idle/low-speed/cruise fuel economy, crisp throttle response, and have a nice lean-best idle mixture as well with the idle mixture screws ~1-1/2 turns out.

    Primary idle air bleeds, the outer brass restrictions:





    In a pinch, I think you can keep the 50cc diaphragm, housing, and lever, and use a pump cam meant for the 30cc accelerator pump. Otherwise, all 30cc components bolt on.

    There were OE Holley two-barrels on some things, but I'm pretty sure 500cfm LIST-4412's were/are only aftermarket carburetors, that version of 'em never OE on anything.

    Quite welcome, good luck with it! Keep us posted...
    Last edited by Walking-Tall; 07-19-2017 at 10:38 PM.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1966 Ford Fairlane sedan
    1966 Ford Fairlane GT
    1981 Mercury Marquis Brougham
    1980 Capri RS Turbo
    1971 Mustang
    1974 Pontiac LeMans

  10. #10

    Default

    Any progress with this?...
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1966 Ford Fairlane sedan
    1966 Ford Fairlane GT
    1981 Mercury Marquis Brougham
    1980 Capri RS Turbo
    1971 Mustang
    1974 Pontiac LeMans

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