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Flathead Carburation

Discussion in 'The Hokey Ass Message Board' started by qmdv, Nov 7, 2012.

  1. I am building a 59A with 283 cu in. about 10 to 1 comp ratio. If you had your choice what would you do:

    1 two 97's
    2 two 48's
    3 three 97's
    4 three 81's

    I have an Offy 2 carb maniford and a Navarro 3 carb manifold. Have lots of 97's one 48 and no 81's

    My instinct tells me two 97's but that Navarro looks so good. Loved Barney's work

    Tim

    Tim
     
  2. Andy
    Joined: Nov 17, 2002
    Posts: 4,471

    Andy
    Member

    Get a 54 Buick 4BBL WCFB. They don't flood or leak and run really strong. They have the velocity secondaries so they don't bog. One of my happiest days was when the 4 BBL went on and the 97's came off.
     
  3. V8 Bob
    Joined: Feb 6, 2007
    Posts: 2,482

    V8 Bob
    ALLIANCE MEMBER

    The Navarro triple is arguably the best out there, and works great running 3 97s with straight linkage. :D
     
  4. porknbeaner
    Joined: Sep 12, 2003
    Posts: 41,121

    porknbeaner
    Member

    Tim how well does the engine breath, it has increased inches and compression but how much are will it draw. Has the block been relieved, monster cam shaft?

    I like the idea of 3 '97s myself, but most flatties will not use them. Your carburation is based on the ability to draw air, if your engine does not take a deep breath it will not need or be able to use very many cubic feet per minute.
     
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  5. Ole don
    Joined: Dec 16, 2005
    Posts: 2,915

    Ole don
    Member

    I ran a 286 with three 97's on progressive. It had Offy heads and a 400Jr in a light car. It was a delight to drive.
     
  6. porknbeaner
    Joined: Sep 12, 2003
    Posts: 41,121

    porknbeaner
    Member

    There Ol Don has used them progressive and it worked for him. He also used a non op cam and better heads.

    I am a big proponent of progressive linkage when useing more than one carb unless you are all out racing with a monster engine under the carbs. Most engines don't want all that air all at once.
     
  7. J.B.
    Joined: Jan 7, 2005
    Posts: 1,246

    J.B.
    Member
    from Sweden

    I am planning a three 97's equipped Navarro on mine for next year.
    Planning on a progressive linkage. Should I go straight instead?
    Thought about the gas speed when using straight linkage in low to mid speeding.

    Had a Thickstun PM7 with two 97's before, but it is way too small.

    The engine is a 296" (3 3/8x4 1/8), relieved and ported with 1,6 intake valves, 400 jr cam.

    The car is a 28 roadster on -32 chassie. Light car.
     
  8. V8 Bob
    Joined: Feb 6, 2007
    Posts: 2,482

    V8 Bob
    ALLIANCE MEMBER


    The Navarro tripple was more of a racing design (no exhaust crossover) and works very well with straight linkage on a built street engine. Mine is only 286", but was built by MCF with Mark's port/relief and 290 dur. cam.
    I at first thought about using progressive linkage, ('cause many said I had to) but was assured I would like straight better, and Mark was right. Around town miliage on my avatar varies from about 8-14, but highway cruising is always 19-20 mpg, in OD @ 2000-2200 rpm, along with crisp throttle response.
    I would at least first try straight linkage, as you can always change to progressive, BTMO. :)
     
    Last edited: Nov 8, 2012
  9. It is 3 3/8 x 4 (286) with Offy 400 heads, ported and relieved with a no name 3/4 cam that was in the engine when I got it. When I first took apart in 1976 I had Kong looked it over, he ran a dial indicator on the cam and said it looked like a Winfield and said to run it.

    Maybe I will go with V8 Bob

    tim
     
  10. smitty city
    Joined: Jun 13, 2010
    Posts: 108

    smitty city
    Member

    i agree with v8 bob, straight linkage, works good on my engine. get with uncle max on here about jets and power valves, i followed his advise and the engine runs great.
     
  11. moonlight graham
    Joined: Apr 17, 2007
    Posts: 155

    moonlight graham
    Member
    from wyo

    Hot Rod Magazine has a really good intake comparison this month. Hart to imagine better timing than that.

    Geoffrey
     
  12. HellsHotRods
    Joined: Jul 24, 2009
    Posts: 1,304

    HellsHotRods
    Member

    I run 3 97's with prog linkage, and Navarro heads.
     
  13. HotRodMicky
    Joined: Oct 14, 2001
    Posts: 1,756

    HotRodMicky
    Member

    I have a 304 ci engine and use 3x97s on straight linkage with a isky 404A (265 dur.)
    Cam

    I would try two 48s or three 97s on straight linkage
     
  14. J.B.
    Joined: Jan 7, 2005
    Posts: 1,246

    J.B.
    Member
    from Sweden

    Any chance on scanning it?

    I don't have it in my local shop over here for a while.
     
  15. no55mad
    Joined: Dec 15, 2006
    Posts: 1,805

    no55mad
    Member
    from nipomo, ca

    Anyone have any thoughts on jetting (what # size jets) for 2 97's on a 59ab? Basically stock engine except for a .030 overbore.
     
  16. JohnEvans
    Joined: Apr 13, 2008
    Posts: 4,883

    JohnEvans
    Member
    from Phoenix AZ

    Back in the 60s I ran 3 94s on a 296CID flattie on progressive got GREAT milage around town. For a thrill I would sometimes hook it up on straight linkage ,WOW talk about throttle response !
     
  17. 40FordGuy
    Joined: Mar 24, 2008
    Posts: 2,908

    40FordGuy
    Member

    I agree with the above posts...3 carbs, use progressive linkage....2 carbs, run straight linkage.

    I'm assuming this is a street machine ?

    4TTRUK
     

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