08. Our bottom end gets fed mass quantities of air via a set of Airwolf 220 CNC heads from Dr-J’s Performance. These are the largest and best flowing non-offset rocker heads currently available, with peak intake flow of over 320 cfm. The OEM rocker, intake, and exhaust configurations make the Airwolf a direct bolt-on. A set of 1.6:1 ratio Erson rocker arms were used for a lift of .589-inch. That is very fast valve action for a 241-degree hydraulic flat tappet cam, but when it was all said and done the cam/valvetrain combo was stable to 7,000 rpm.