6. All cylinder-head improvements were verified on a Super Flow 600 flow bench to note any changes. We found that little things count. Significant increases in airflow resulted from small things like back-cutting the intake and exhaust valves. Overall, the porting was very successful, yielding much improved flow at the lower lift numbers. Remember that peak lift is only a brief moment in time, so the more air you can move while the valves are only partially open, the more full you can fill the cylinder.