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Multi Carb Flathead question

Discussion in 'The Hokey Ass Message Board' started by 64gtoguy, Feb 26, 2011.

  1. 64gtoguy
    Joined: Aug 22, 2008
    Posts: 277

    64gtoguy
    Member

    I'm in the process of changing the carburetion on a Flatmotor. I am thinking I want to go with the 2X2 setup, My question is, what has to be done to the secondary carb ? Is there a way to disable the idle circuit? or is it necessary. I know on 57 and later carbs there isn't an idle circuit on the secondary carbs. Any help is much appreciated.
     
  2. Mnhotrodbuilder
    Joined: Jul 12, 2010
    Posts: 1,142

    Mnhotrodbuilder
    Member
    from Afton, MN

    What type of carbs and 2x2 set up are you going to use? Is you engine stock?
     
  3. J'st Wandering
    Joined: Jan 28, 2004
    Posts: 1,772

    J'st Wandering
    Member

    From your picture I am assuming the the flatmotor is a Ford V-8. Just run them together. Three carbs run progressive linkage, two carbs run them both the same. I didn't look what carbs you are running. With Strombergs, bolt them on and go. With Holleys, I don't know since I don't run those. I am sure someone can help you with what is needed if that is what you have.

    Neal
     
  4. 64gtoguy
    Joined: Aug 22, 2008
    Posts: 277

    64gtoguy
    Member

    The motor is a Merc. mild cam and standard bore. Edelbrock intake with Holley carbs. I plan on fabbing s progressive linkage so I can run off the front carb. untill I need the back one. Can this be done without causing the back cylinders to be lean while the back carb is not in use? I guess this takes me back to my original question about whether or not I can block off the idle circuit on the rear carb.
     

  5. flatjack
    Joined: Feb 13, 2007
    Posts: 957

    flatjack
    Member

    It would depend on the design of the manifold. If there is a common plenum or suitable passage between the 2 risers you could do it. However I would always run 2-2s on straight linkage.
     
  6. Mnhotrodbuilder
    Joined: Jul 12, 2010
    Posts: 1,142

    Mnhotrodbuilder
    Member
    from Afton, MN

    Run them together you will be glad you did it's easy to set up and it will not be over carbed. I agree with running progressive linkage with 3 carbs on a mild flatty.

    I thought the same thing you did about running to lean on one end than the other. flatjack said it right that it depends on the design of the manifold.
     
  7. Straightpipes
    Joined: Jan 25, 2006
    Posts: 1,084

    Straightpipes
    Member

    I run straight linkage on mine with two 97s. You will have to jet them as necessary. I only choke one carb.
     
  8. overspray
    Joined: Jan 14, 2003
    Posts: 1,302

    overspray
    ALLIANCE MEMBER

    Holley 94's PM Dickster27 and let him know what carbs, cam, heads, distributor, you are running. I sent him my flathead info and he set me up with the correct power valves and jets to make it run great without the hassle of me trying my own jet/power valve combos by trial and error. I run my 2X2 set up straight linkage and I had GMCBubba build me a distributor for the flathead (reworked SBC/no vacuum advance) and it runs and idles great. I adjust the idle circuits on both carbs "by ear", which is real easy and fast. It gets better fuel mileage now than when I had 1 carb, plus more power. According to the color of my plugs, the fuel distribution is pretty equal to all cylinders.

    overspray
     

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