Quote Originally Posted by BigTruckDriver
Is this pretty much with a street engine ,daily driver, or is it also with a race engine??

That's with any engine. Of course, the bigger the cam the worst reversion will become an issue. An 1/8" lip on the bottom of the intake runner has the most anti-reversion benefit. It's also beneficial if the headers are about an 1/8" below the bottom of the exhaust port.