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Technical Banger with dual 94's

Discussion in 'Traditional Hot Rods' started by captain j, Feb 3, 2015.

  1. captain j
    Joined: Dec 21, 2008
    Posts: 125

    captain j
    Member

    I know there's a ton of info and I've gone though countless hours of searching.
    I'm running a 31 model a 4 banger.complete Rebuilt enginewith 5:1 high compression head, centrifugal advance new distributor, 12 volts, full headers, and Riley dual carb intake with dual Holley 94's.
    My question is to those who are running a dual carb intake on a 4 banger what jets and power valves are you running? And how does it run. From what I have read I plan on going with 3.5 power valves and maybe 46 or 48 jets. Thanks.
     
  2. modelAsteve
    Joined: Jan 9, 2009
    Posts: 359

    modelAsteve
    Member

    Way to much carb- go to 97's or even better 81's
     
    gwhite likes this.
  3. captain j
    Joined: Dec 21, 2008
    Posts: 125

    captain j
    Member

    I already have 4 good working 94's. Don't want to spend a small fortune on strombergs. I don't see why just jetting down the 94's wouldn't work. I know the cfm of 2 94's is a bit more than the 97's or 81's
     
  4. 5:1 isn't much of a bump over the stock CR (4.22:1)...you're way over carbed. You'd be better off with a single carb rather than duals for all but the most radical banger setups IMO.

    I'm running a .025" milled Winfield 6:1 head on a .060" over A motor (final compression around 6.3:1) with an SU-1R cam (Winfield 3/4 grind)...I figure around 125-150 cfm (single Stromberg or Winfield "B" carb) will be ideal.

    I'd sell the 94's and Riley intake (I'm assuming it's a reproduction) and go with an 81 or a 97....
     
    Hitchhiker likes this.

  5. boo
    Joined: Jul 6, 2005
    Posts: 557

    boo
    Member
    from stuart,fl.

    on my A im running 60 over bore, snyder 5.5 head, crane 302 cam,winfield dwn. draft intake w/48 ford 6 cyl. carb 1 barell, matches the intake bore perfict , B distributor, runs great. carb made for approx 221 cu in, about what i have w/A eng. Was at a hillclimb in chattanooga, a fellow running 2 97's took one off and stuffed a sock in one hole and ran just one carb and had a faster time.
     
    captain j likes this.
  6. I had 2 94's on my ol banger I had 6.3 compression stock b cam it was bored out to 80 thousands
    it ran but not proper It had no low end tquork very flat
    I went to a single 94 it was better but not good
    I put an 81 and it ran good
    I tried 2 1 barrel's it was almost ok to drive
    finly left it with a 1 barrel
     
  7. Try it and report back your honest experience. I'm curious how it goes.

    Posted using the Full Custom H.A.M.B. App!
     
  8. 5280A2
    Joined: Sep 8, 2014
    Posts: 127

    5280A2

    I am running two 94's on my Model A with 7:1 compression and a Brierly cam with the Winfield SU1R grind. Contrary to popular opinion jetting down on the main jets is the wrong way to go. With two carbs you are halving the airflow through each carb which reduces the vacuum signal substantially, so the carb loses some ability to pull fuel through the main jets. I went to 3.5 power valves and think that is the correct answer for an A or B with a streetable cam. My car ran pretty well with the stock #51 main jets with just a bit of off-idle hesitation that couldn't be overcome with the accelerator pumps. After changing from a Thrush turbo muffler to a steel pack (more bark less back pressure) the hesitation got more pronounced. On the advice of a buddy running Strombergs, I went up in main jet size to eliminate the bog. I went to #54's and it cured the low end issues completely. However, the bigger jets made the top end too fat and I would get some high speed miss that hadn't occurred with the smaller jets. Finally swapped one jet in each carb back to stock #51 rather than buy a complete set of jets between the stock size and the #54's. With this change it runs great on both the top and bottom end. Although it now runs well, it still will foul out a set of plugs in less than one driving season. Here in Minnesota that means maybe 1000 miles tops. I'm willing to buy a set of plugs at that frequency for the kick-in-the butt fun of driving a hopped-up banger! I've gone a little hotter on plugs than the initial recommendation that came with my reproduction Winfield head without solving the sooty plugs, so I have some more experimenting to do now that I feel like the jetting is good.

    There is no question that your car is over carbed; so is mine, so are most A and B street-driven four cylinders with dual carbs. I get it that that may not matter to you. I'm a little concerned that you may not get dual carbs to work without more compression or more cam, but it's worth a try. My recommendation is use your 3.5 power valves and see what it does with the stock jets. If that bogs off idle go to #53 or 54 jets and try that. Good luck!
     
    grego31 and captain j like this.

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