New cam lobe designs allow maximum performance for Evolution engines Give great throttle response and mid-range with excellent high-rpm power Fast opening and closing gives better airflow with the lift and duration used Xtreme Energy cams require valve springs designed for high-lift cams All cams made from SAE 6150 bearing-quality steel for durability and include the cam gear Made in the U.S.A.. V-THUND EVL5005 CAM 84-99