That suggestion by Mr. Vizard sounds interesting and I can understand part of his reasoning in that there may be as much as 80% of the 'hotrodders' running very expensive motors with an imbalanced equilibriam between the insky and the outsky And with this imbalance the volumetric efficency is way down. As we all know,there are mismatched parts combinations,insky and outsky sides both,and maybe this is the reasoning behind his suggestion? (I don't understand half of what I know about this so correct me if I'm wrong). Or maybe his reasoning is to match the overlap to the flow capability of the motor .
But I can't even start to understand why he would suggest designing around overlap unless it would pertain to a specific class race motor?