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IIRC the quick way to know the size is if the plates are all the same size, it is a small carb, if they are different then it is the bigger one.



I don't think this statement accurately captures the different sizes. The large AFB will have 1 11/16" primary and secondary throttle plates.



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Dave when I measured my throttle bores & got the 1&7/16/1&9/16 that's what made me think that it was supposed to be the throttle bores & not the venturi's. I stand corrected





1 7/16 & 1/9/16 is a small AFB. I don't think there was anything from 66 that had the large AFB.