In a time ,probably late 70's, I ran some tests on the effects of various size and shape tubes, on the airflow, and fuel atomization. Of course, the diameter of the tube, and too some extent, shape, affected CFM. But what got the attention of the engineer, was how fuel atomization was changed down stream of the tube. One reason I like Jay's raised intake port, with no pushrod tube. Of course this testing was steady state, airflow in a pretty much straight port, and not a true tunnelport head.