K&N Custom Air Filters for Single or Two Barrel Carburetors - K&N custom air filter kits are designed to boost performance from your carburetor while keeping the dirt on the outside where it belongs. These assemblies come with custom chrome top and base plates and the famous K&N High-Flow Washable Air Filter. K&N Custom Air Filter kits are designed to boost the performance from your carburetor while keeping dirt on the outside where it belongs. These assemblies come with custom chrome top and base plates and a K&N washable air filter.