I've dyno tested two different 440 motors on two different dyno testing the 14 inch K&N filter tops, both motors lost 8 HP with them on in the dyno room confused
At the track with a air cleaner that the metal top was close to the back of the hood scoop the car picked up .03 ET and .2 MPH on back to back test at LACR years ago work up

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)