The increase in airflow provided by the filter results in a 3hp gain on factory displacement M8 engines, up to 5hp gain for 124″ big bore M8 engines. Fits oval Screaming Eagle Ventilator air cleaners and M8 special models equipped with oval air cleaners. Performance air filter upgrade for factory HD Ventilator oval air cleaners. Includes spacers and everything needed for simple installation. 22% more air filter surface area than factory.