A tumble port adds another dimension to the flow of the intake charge. We've all heard of swirl ports, which impart a curving swirl to the charge to help it mix when it enters the chamber.

Think of a tumble port as making the charge do a somersault when it comes in the room.

Tumble ports are not really new, Ford had them on some of the 4.6 and 5.4 32-valve engines of the late 90s-early 00s.