yes--the original vents from Moroso had three check valve/anti backfirevalve--- one for the whisle by the collector and one in a hose to the intake(kind of like a PCV) My prostock prostock had two instrument up by the tach--oil pressure and vacume--always looked at all three readings as I crossed the line--could tell by rpm how fst and hp , if not up where it should be vacume/oil pres were clues