I don't see how you can flow enough through the side to side's to make the HP, but obviously Juan and Bello are doing it so I guess my math is off.
It really seems like it doesn't matter. Side to side, the air travels farther in the IC but the velocity is higher. Back to front, it doesn't go far but the velocity is low. It seems like the intake air spends about the same amount of time in either configuration.
Maybe someone who's spent too much time figuring on this can chime in
