I think that all of the vacuum connections under the upper manifold share a common vacuum source, have the same vacuum signal, and can therefore be interchanged. It is really just a question of finding a decent connection for each hose in terms of size of nipple, and hose routing. And yes, I would connect the charcoal canister. If it does not proerly purge, I believe that the chrcoal will become saturated with gas and start to stink. That's what mine did when the hose under manifold failed from age and ceased to pull vacuum through the canister.