Late model "F" carb Vs. 2F carb.

Discussion in '40- & 55-Series Tech' started by Josie'sLandCruiser, Jul 4, 2005.

  1. Josie'sLandCruiser

    Josie'sLandCruiser Stop calling it a "FJ."

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    Hi All:

    My FJ40 has a '78 2F engine swapped-in by the previous owner. He re-used the '74 late-model "F" engine carb on the 2F engine. This carb has worked well i nthe past for me, but appears to need a re-build now (what, only 30 years of use!?!)

    I have the option of either having this late-model "F" carb rebuilt, or an extra '78 2F carb re-built. Any opinions of what is the better option to follow?

    The late-model "F" carb is a bit smaller than the '78 2F carb, but is also simpler (the '78 2F engine is de-smogged.) The 2F carb I imagine could potentially produce more power, since it is bigger, but I've also heard that the late-model "F" carb will produce better fuel economy.

    I'd appreicate anyone's comments and/or suggestions.

    Regards,

    Alan
    Seattle
     
  2. CruisinGA

    CruisinGA

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    The '74 has mechanical secondaries. For that reason alone (there are others) I would stick with it.

    Supposedly easier to rebuild/repair.

    Should flow plenty of air for a 2F.
     
  3. Degnol

    Degnol

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    I agree with Bailey and I think you should send that carb to Marksoffroad.net or Jim Chenoweth. If you tell them what you are going to do with it, they can fix you up and even drill the base for a ported vacuum so you can run a vacuum advance dizzy.
    GL

    Ed
     
  4. amandap

    amandap

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    I have the same dilemma on my new 78 2f into my 66FJ40. I spoke with Jim C about it and he convinced me to stick with the 78 carb, which is on it's way to him now with the 78 dist. I really do like the looks and simplicity of the older 74 carb tho. Maybe he'll chime in here but I think he said that the cfm's are different and the 78 will give quite a bit more power. If I remember correctly I think he's going to do something with the vacuum port also? I won't have anything to compare it with other than the old F setup so I'm sure it'll be better than that.
     
  5. FJ40Jim

    FJ40Jim The Cruiser Whisperer SILVER Star

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    To keep your life simple, just rebuild the 74 carb for the '74 truck.

    If you want to complicate your life, swap on the '78 carb, fuel lines, air cleaner, insulator plate. The truck will run a little better and get slightly better fuel economy, but it would entail a lot of scrounging of small parts to make it fit right.
     
  6. rocknfj40

    rocknfj40

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    i am facing the same problem. I rebuilt the carb on my f engine thinking i would swap it onto my 76(f2 engine) Now i have recently purchased a 77 for parts with a fresh engine but the guy has patched a cm carb onto it. most people are telling me to use the old style for simplisidy. don't know if this helps you at all. Good luck rocknfj40
     
  7. honk

    honk

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    As Jim advised, the small parts of the various linkages can really add up when going from year to year with cruiser carbs. Some of the small pieces to make up either the swivelling rod type or the rod/cable/bellcrank/rod type are over $30.00 per part at SOR and SOR is the only place I know that will reliably have what might be needed. Sure, the pieces pop up in ebay from time to time, but it's surprising how many people there are apparently looking for them. Prices there easily end higher than SOR prices and you can't be completely sure what you'll get.

    If you have a working throttle mechanism and a carb to go with it, stick with it. The fuel milage difference won't hardly be noticable.
     
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