Carubretor Replacement- 350 / 5.7

Discussion in 'Mechanic's Corner' started by jtoolan12, Apr 15, 2019.

  1. jtoolan12

    jtoolan12 New Member

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    Mar 27, 2019
    Need to replace old carburetor on Chevy 350 5.7

    Electric Choke and vacuum secondary, dual fuel inlet.

    What's the difference between mechanical secondary and vacuum secondary?

    Any suggestions on what I need? I am being told all I need is 600 CFM?

    Thanks for your help.
  2. Shamrock Steve

    Shamrock Steve Well-Known Member

    Likes Received:
    Jan 31, 2014
    Make sure you are buying a Marine Carburetor with inverted J -tube, so it is USCG safety compliant. Most people are using Holley or Quick Fuel, some have had good luck with the Edelbrock. For new I usually shop Jegs or Summit and try to catch a sale. If on a tight budget you might consider a re-manufactured unit or perhaps send your unit out for a rebuild.

    The vacuum model uses the engine vacuum to open the secondary; whereas the mechanical uses the carburetor linkage. Best fuel economy is associated with the vacuum secondary units. I've only used mechanical secondary units on high performance engines for strip use.

    Good Luck,


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