Welp! I guess know one knows so I found the answer myself. Now I will share it with you. "At the end of each intake runner was a new-to-Mustang feature Ford called a charge motion control valve. At low engine speeds and light loads, these specially shaped control flaps closed to speed the intake charge and induce a tumble effect in the combustion chamber. That caused the fuel to mix more thoroughly and burn more quickly and efficiently. At higher engine speeds, the charge motion control valves opened fully for maximum flow into the combustion chambers."