are you going to try to use the stock top? i lost 2 full tenths running a new paper air filter in the stock housing with the lid tighten down and sealed. Most F.A.S.T. guys i see with that cleaner run a filter thats maybe a 1/4 to 1/2 " taller which makes the lid have a gap allowing a lot more air into the engine than the two small oval cutouts.