Pick up a June issue of 5.0 Mustang Magazine, Pg.143. They do a dyno test of the Victor vs RPM vs Air Gap on a 392 stroker. The Air Gap made about 5 more horses across the board and only a couple ft/lb of torque than the RPM. That's not much for the money. The Victor peaked 5 higher on HP, but was about 15 ft/lb down on torque.
buyer beware, you have to compare apples to apples especially when it comes to intakes. the RPM/RPM AirGap manifolds produce power from 1500-6500 if i am not mistaken the Victor Jr. does not operate within the same RPM range.
the AirGap desing is to keep air/fuel mixture temperatures at a lower (more desired level) underneath the manifold. this desing is nothing new, check out some early 70's Hemi's if i am not mistaken. the AirGap is a pretty manifold...just make sure you have enough hood clearance
bamm bamm...i purchased a rpm air gap 4 my engine and written in the literature supplied with the manifold stated it has larger runners than a normal rpm,as i didnt compare the air gap to my old rpm i cant say for sure,as n20 mike said they dont,he probably would know more than myself,and before you ask what did i think of it i didnt use it...sorry