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quadrajet cfm?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Dunc03, Jul 14, 2002.

  1. Dunc03

    Dunc03 1/2 ton status

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    Any body have a clue what kind of Cfm's a quadrajet runs. Its on a 86 k5 with a 305, it's a four barrel . Thanks forthe help
     
  2. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    The quad will only flow as much as the engine demands...as far as I can find they came in two sizes and can be identified by the primary butterfly diameter. the 1 3/32" primary carb is 750 CFM max and probably what you'd find on your 305, the 1 7/32" primary carb is either 795 or 800 cfm depending on the source.

    Rene
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

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    Actually not to be a nit picker, but all (wow, like 3 lol) truck 305 carbs I've looked at are 800CFM units. Nothing to brag about though, that hurts your MPG, (compared to a 750)and on a 305, the engine will never demand 800CFM. (I'm using 800, easier to type than 795 lol)

    However, the one I had on my '83 ran like a champ after I rebuilt it, and gave me an all-time high for that truck of 17MPG.

    Oh yeah, forgot. By the late 70's, GM was mechanically limiting the secondaries of these carbs to an estimated 650 or so CFM, and if you compare different years/applications, the "limit tang" on the secondary air valve shaft (passenger side top) got longer and longer.
     
  4. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Nit picker... /forums/images/icons/grin.gif /forums/images/icons/wink.gif

    Rene
     

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