Single plane vs dual plane intake

It is in the design how well any intake works. Holley did their homework and their distribution is pretty close. Other intakes need mods to get the distribution right, look at the Racing Manual for fixes for distribution mods in SS intake manifolds. Single Plane Holley Street Dominator is good for low end and a Torker is a power loss throughout the rpm range compared to a stock cast iron dual plane. Generalizations don't quite cut it anymore. There are also correlations between effective runner length and rpm efficiency. In the end, it is not an easy comparison.