Charcoal cannister

No reason to plug off anything, the ’73 and up three nipple canisters used a dedicated ported (above the throttle blades) purge connection on the OE carbs. Without the OE carb you can tee into the PCV line but will need to place a restriction in the purge line of about .030”. Anything bigger will mess with the mixture calibration. It won’t purge as fast but will purge and not affect engine efficiency.

Optionally, you can run a ’72 four nipple two-stage purge canister, if you can find one in good working order, for a full purge rate. Tees into the PCV and vacuum advance lines.