Compared to the as-cast 190 cc heads, the CNC-ported 215 heads offered more flow everywhere. The CNC version improved the peak airflow by 45 cfm on the intake and 25 cfm on the exhaust. More importantly, the flow numbers improved throughout the entire lift range. While more peak lift flow is good, more average flow throughout the lift values is even more important. Using the power versus airflow formula (HP=airflow x .257 x number of cylinders), the CNC porting improved the power potential by 58 hp over the as-cast heads.