Venturi ID and Sizes - AVS Carb

Fuel and Air Systems

  1. roadrunner57

    roadrunner57 Well-Known Member

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    While refreshing my AVS in anticipation of starting my 440, I noticed the Venturi numbers are different. They are: 1307 & 1273. What is the significance of the numbers? Do they relate to sizes? Why would they be different?
     
  2. RJRENTON

    RJRENTON FBBO Gold Member FBBO Gold Member

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    Are you referring to the casting number/stamping on the PRIMARY BOOSTER VENTURII ? Generally the numbers are consecutive, right side and left side. There are exceptions however. SOMETIMES there is a mixture distribution tab attached to one of the booster nozzles, for the purpose of directional flow compensation to the manifold runners to help with equalization of the fuel distribution. In addition, the booster venturii assemblies are left-right oriented and cannot be interchanged. The primary booster venturii also furnish 100% of the idle & off idle fuel mixture to their respective circuits.
    What is the carb's number..... like 4428S or 4449S or something similar. There are minor variations from year to year, as the numbers change.
    BOB RENTON
     
  3. roadrunner57

    roadrunner57 Well-Known Member

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    Yes, the two venturi's, 70 440 RR with automatic trans and AC. I have an AVS 4640 SA. It is logical that the numbers are similar, cannot find anywhere that really discusses them. It's like you need a secret handshake or something. Any idea where to find detailed info on these cute little critters?
     
  4. RJRENTON

    RJRENTON FBBO Gold Member FBBO Gold Member

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    Several years ago, Federal Mogul published on 6-82, a booklet Form # 3703A which explains all the workings of the the Carter AFB and AVS designs. This is available on line from a suppliers. What individual omponents's part numbers are that were used on specific carbs is very difficult to find. These may help.
    Www.thecarburetorshop.com or
    Www.carbkitsource.com
    My reference shows Carter 4640S Used on 1969 440 with A/C carb has the hot idle compensator and a anti diesel solenoid. It had 1 11/16" diameter primary and secondary throttle plates. Set up details are noted in the FSM....main jets, step up rods, secondary metering jets, float settings, etc. Primary booster idle feed restrictions are usually 0.035" dia.. but can vary depending on if its a CAP/ CAS carb or 49 states.
    Hope this helps.
    BOB RENTON
     
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