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  #18  
Old 09-26-2021, 03:50 AM
Geoff Geoff is offline
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Join Date: Jul 2005
Location: Australia
Posts: 2,471
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If you are getting a 'gassy' smell with MVA, then you have an adjustment problem, not an MVA problem. These 64-66 AFBs that Pontiac used did not have an idle speed screw; the boss is there for it on the side of the carb, but is not drilled. You could drill & tap for a speed screw.
In it's factory configuration, the pri t/blades seat in the bore. The large brass screw adjusts idle air flow to adjust idle speed. Using a proper speed screw as outlined above will give you more adjustability.