Charcoal canister, help me understand.

73 duster 225, one line runs to carb vent, Holley 1920, one to tank vent, and the purge line is capped off. Where is the purge line supposed to go? Manifold vacuum? Teed into the ported manifold line running to the distributor? The factory emissions controls has been deleted by me but I bought the car with the canister purge capped off. Not sure if this is related but after I shut the car off the fuel drains back into the tank almost immediately, makes starting the car a real treat.