Geyser...if the quadrajet is an original 1968 Q-jet, it at one time had a vent/valve that was actuated by the accelerator pump, located on top the carb near the inlet. It was decided by carb builders that the this valve did little more than let dust into the fuel bowl so many simply plugged the opening with a brass plug and epoxied it from leaking, and discard the little valve mechanism.
If this is what you're referring, buy a new plug...a O-ring type plug is available, but a replacement brass or steel one is fine if used with epoxy. You'll need to remove the air horn.
1969 and up didn't use this vent set-up.