What hooks to this port in the carb?

[sixpack_sid]

I am hooking up the carb on my 440 eng from a 77 NYer. The eng is in a 68 Charger. This one port, I don't know what goes here. See pic.
Anyone know what goes here?

[resq302]

When I had that carb on my car prior to getting a factory correct one, mine was just left open like that.  I think it was a vent of some kind?

[tan top]

thats part of an ECS  , forget now but think its connected to  the oil filler cap & vapour lines going back to tank & or a charcoal canister , depending on what model    ,  
 some leave it open  , if car is not fitted with ECS , don't like the idea my self  , think i would look for a nother top to the carburettor if you not connecting it to anything , but i'm nutts like that