 The length of the stack is known to have a direct effect on a particular engine's boosted power range.Most current aftermarket stacks are designed to be run "in" the airbox and a company that does research well will have some applications that have all the same length and some applications that have differing lengths of stacks on different cylinders.It is commonly related that "stand off" (air–fuel mix that gets pushed back out of the port, usually at full throttle / low rpm) is somehow captured by installing a longer intake pipe (stack).