Edelbrock 500cfm on factory 273 4 barrel manifold

Fuel and Air Systems

  1. rkjjeep

    rkjjeep Well-Known Member

    Messages:
    94
    Likes Received:
    43
    Joined:
    Jul 25, 2019
    Location:
    Pinckney, MI
    Local Time:
    12:00 PM
    A previous owner rebuilt this 1965 273 to commando specs and installed the factory 4 barrel cast iron manifold and a new Edelbrock model 1403 CFM carb. Seems to fuel really well. Any idea if or why it required the 1/2" thick aluminum spacer between the carb and manifold? I'll post a picture later. Thanks
     
  2. toolmanmike

    toolmanmike FABO Staff Staff Member FABO Gold Member

    Messages:
    46,879
    Likes Received:
    31144
    Joined:
    Jan 18, 2006
    Location:
    Iowa
    Local Time:
    11:00 AM
    The secondary butterflies won't open without an adapter on many 273 intakes.
     
    • Agree Agree x 1
    • rkjjeep

      rkjjeep Well-Known Member

      Messages:
      94
      Likes Received:
      43
      Joined:
      Jul 25, 2019
      Location:
      Pinckney, MI
      Local Time:
      12:00 PM
      Got it. The manifold is 2465726. See picture below.
      carbspacer.JPG
       
    • B-onefan

      B-onefan Well-Known Member

      Messages:
      1,298
      Likes Received:
      88
      Joined:
      Oct 2, 2009
      Location:
      Texas
      Local Time:
      11:00 AM
      The butterflies valve on the bottom of the carb hit the holes in the intake without the space. Plus to help with heat transfer
       
      • Agree Agree x 1
      • toolmanmike

        toolmanmike FABO Staff Staff Member FABO Gold Member

        Messages:
        46,879
        Likes Received:
        31144
        Joined:
        Jan 18, 2006
        Location:
        Iowa
        Local Time:
        11:00 AM
        Here's my 66 manifold after machining. Without machining (or an adapter in your case) the secondary butterflies didn't open all the way.

        clutch kit 019.jpg
         
        • Agree Agree x 1
        • rkjjeep

          rkjjeep Well-Known Member

          Messages:
          94
          Likes Received:
          43
          Joined:
          Jul 25, 2019
          Location:
          Pinckney, MI
          Local Time:
          12:00 PM
          Got it and thanks. I often make the mistake of thinking these new carbs really are AFB's.
           
          • Like Like x 1
          1. This site uses cookies to help personalize content, tailor your experience and to keep you logged in if you register.
            By continuing to use this site, you are consenting to our use of cookies.