Vibrant Performance 2.5" Aluminum Bellmouth Velocity Stack & Air Filter Vibrant The Classic Performance Air Filter (5.25in O.D. Cone x 5in Tall x 2.75in inlet I.D.) Vibrant Performance Open Funnel Performance Air Filters K&N Filters RC 5000 Oval Cone Air Filter Fits GM TPI LT1 Throttle Body. Vibrant Performance classic standard air filters feature a 4ply pleated cotton gauze element that allows for significantly more airflow than a stock filter while providing excellent filtration of airborne particulate. Each filter is pre oiled, washable and reusable. Vibrant Performance classic standard air filters are an excellent choice for turbo charged applications and are available in Inlet I. D. Diameters ranging from 2. 25 to 4. 5.