Hi, I am restoring a 1971 AMX. and have resently done research on this in books and a un restored 1971 car I have to look at. The vent line is not attached to any thing. What you see is a filter is really a roll over valve in the shop manual, they call it a check value. I don't think hooking the vent to the carb would be wise. It would cause the check valve to close not allowing air into the gas tank. I am no expert, but i am a 40 plus year plumber, like pipes, tanks need to bleed. Hope this helps. Mac