I think what you're saying is that if the lid to the air cleaner is so close to the top of the carb that it's creating the choke point for air flow, then dropping the bottom of the air cleaner housing, and installing a filter with more surface area is not going to improve air flow, or performance and I agree with that analysis. If the top of the air cleaner assembly is indeed causing choked flow you could remove the air filter element and the flow would remain unchanged at WOT, and the only way to improve flow is to lift the lid to give less restriction to the air flow over the top of the carb, into the venturi's. Sorry if I've mis-understood your basis.