Its not so much large cfm = equals less low rpm power, its more of a large venturi = less power at slow speeds.
This why GM installed Q-jets on all there engines. The small primary's kept the air velocity high during low speed driving and the big secondaries move the majority of the air at high speeds. Its all about fuel atomization the carbs ability do that all speeds. Large bore venturies just don't do a very good job of it at slow speeds.
Joe
