K&N Performance Cold Air Intake Kit 57-2541 with Lifetime Filter for 1997-2004 Ford F150/Expedition, Licoln Navigator 4.6L/5.4L V8 Estimated horsepower gain of 13.12 HP at 4562 RPM Designed to improve throttle response and engine sound Lasts up to 100,000 miles before service is required (depending on driving conditions) Replaces entire factory air intake system Easy to install, usually in 90 minutes or less