Need Help on Carter 4620 AFB Secondary Venturi Question

[Dragon Slayer]

I am rebuilding a 1969 Carter 4620 AFB. I have the technical document that list part numbers so I could compare installed parts against the technical sheet.

The problem I have is the pump side secondary venture is not the part number correct piece. It is a 348 which I believe would have been on the 66-67 equivalent AFB car.

So here is the problem, the Opposite pump side venturi is unique in design, and does not have the initial discharge port inside the venturi triggered by the air valve. The 348 does, but it has different hole design.

Did carter move away from an initial discharge port on the secondary, or is my part number correct version a defect?

Does someone have pictures from a carb restoration to show original 4620 secondary venturis?

I have seen several AFB secondary's from various years that have different configurations, but this 4620 seem unique. I have attached some pictures for comparison. The first is the base, which has an extra hole closer to the airvalve that most other AFBs do not have. The original venturi is on left with 2 tubes, the others are different versions. The original is on the right, in the later pictures when I show the initial discharge port on the venturi. Thanks,

 

[mmissile]

Shouldn't 69 be an AVS?

 

[Dragon Slayer]

Shouldn't 69 be an AVS?

Not all of them. AVS do not have removable secondary Venturis or Aux air Valve

 

[miller]

I'd try to look up a spec sheet on your 4620, to see what stock #s are for the venturi.
Know there's alot of AFB info online.

 

[Dragon Slayer]

I'd try to look up a spec sheet on your 4620, to see what stock #s are for the venturi.
Know there's alot of AFB info online.

Thank you, any additional info would be helpful. I do have the Carter Form for this carb that identifies part numbers. I have been doing internet searches, but some of this more detailed technical information really is not covered.

What I did find out, though is the initial discharge port is actually in the base under the air valve. That is why there is an extra port. Most AFBs I have seen, the discharge is above the air valve inside the ring of the secondary venturi. That is what had me going. Who ever worked on this carb before me, but the wrong venturi in the pump side secondary.

I got lucky and found a 63 GM AFB a buddy had, and it used this same design. Turns out the secondary venturi's are a match despite different part number. So I can get this one right.

Funny how many variations of the same carb carter used, and why something used in 63, stopped being used for many cars, and than comes back for the 68-69 cars.