super six carb ?

There are full PDF manuals for the BBD and Holleys over at slantsix.org . Also a few movies. I think Chas is right it should be the bowl vent and hooked to the charcoal canister. As long as it didnt break further down you should be OK.
I would look for a better carb to rebuild and have that one on hand as a spare if it were me.
Frank