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Best carbs for a 3x2 on a 327?

Discussion in 'The Hokey Ass Message Board' started by Gleeser, May 26, 2010.

  1. Gleeser
    Joined: Oct 17, 2005
    Posts: 465

    Gleeser
    Member
    from Taylor, MO

    I want to run a 3x2 setup on my relatively hot 327 that's going in a Model-A. Trying to decide which carbs to run on it. I'm wanting to make relatively high cfm as this motor is pretty heavily built.

    What kind of numbers can you get out of 94's & 2G's?
     
  2. RClark
    Joined: May 14, 2006
    Posts: 147

    RClark
    Member

    I'd run 2g's. Well actually I do. They're cheap, easy to get ahold of and, when run progressive, easy to tune.
     
  3. Blue One
    Joined: Feb 6, 2010
    Posts: 10,966

    Blue One
    ALLIANCE MEMBER
    from Alberta

    If you want performance then a Barry Grant six shooter with 3- 250 CFM Demon carbs would give you what you need.
     
  4. draggin'GTO
    Joined: Jul 7, 2003
    Posts: 1,762

    draggin'GTO
    Member

    I'd opt for the Rochester 2GC carbs.

    You can run 3 of the small-base carbs and end up with about 600 CFM ('57 347 & '58 370 Pontiac Tri-Powers used this setup).

    Or run one small base in the center and 2 of the large base carbs for the end carbs and end up with about 750 CFM ('59 -'65 389 & '63 -'65 421 Pontiac Tri-Power).

    Run all 3 large-base carbs for around 800 CFM total (the '66 389 GTO & 421 Tri-Power big Pontiacs came this way).

    I'm using Pontiac factory setups for reference here since I'm familiar with them.

    Three of the 94s will only net you about 450-500 CFM total.
     

  5. 33_chevy
    Joined: Aug 30, 2008
    Posts: 370

    33_chevy
    Member
    from TX

    Any one know what the cfm,s on 97's...I'm running 4 of em
     
  6. Gleeser
    Joined: Oct 17, 2005
    Posts: 465

    Gleeser
    Member
    from Taylor, MO

    Thanks much man. That's helpful. According to the builder I want to be in the 650-700 range for this particular engine.
     
  7. uncle max
    Joined: Jan 19, 2006
    Posts: 905

    uncle max
    ALLIANCE MEMBER

    Old original 97's run 150 cfm's. The New English 97's flow 162 cfm's.
     
  8. 33_chevy
    Joined: Aug 30, 2008
    Posts: 370

    33_chevy
    Member
    from TX

    Thanks uncle max...
     
  9. chubbie
    Joined: Jan 14, 2009
    Posts: 2,311

    chubbie
    Member


    my information says that the 2G's are 280 CFM, x3 is 840 CFM
     
  10. draggin'GTO
    Joined: Jul 7, 2003
    Posts: 1,762

    draggin'GTO
    Member

    Small or large base?

    I've seen the '66 Pontiac Tri-powers (3 large-base carbs) listed by different knowledgeable sources at anywhere between 780 and 888 cfm for this unit.

    Either way, the 2G Rochesters should be the best way to get 700+ CFM.
     
  11. chubbie
    Joined: Jan 14, 2009
    Posts: 2,311

    chubbie
    Member

    thats a small base 2G @ 280 CFM. 840 is a lot of CFM on 327 cubes, but works OK. some times its hard not to open them up between all 4 gears!
     
  12. Abomination
    Joined: Oct 5, 2006
    Posts: 6,701

    Abomination
    Member

    I agree with not going with 97s or Holley 94s.

    I'd go the Stromberg WW/Carter BBD/Rochester 2G route - especially the latter, due to availability of off-the-shelf 3x2 setup goodies.

    ~Jason
     
  13. Shaggy
    Joined: Mar 6, 2003
    Posts: 5,208

    Shaggy
    Member
    from Sultan, WA

    I'm going stromberg 48's on my 283

    No reason (exept mabey space) you couldnt go newer style holley 2 bbls either
     
  14. rhpope
    Joined: Oct 22, 2007
    Posts: 73

    rhpope
    Member

    2 bbl carbs flow rate are at 3.0 in Hg not 1.5 in Hg like 4 bbl carbs are rated so the comparison is wrong.

    4BBL Flow = 2BBL Flow / 1.414.

    For example: A 500 CFM 2BBL Carb actually flows 353.606 CFM on the 4BBL scale


    Roger
     
  15. bigsam63
    Joined: Dec 22, 2005
    Posts: 171

    bigsam63
    Member

    Gleeser,i run the 2G's with the progressive from speedway works just fine.
     

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