David Vizard's How to Port & Flow Test Cylinder Heads. Author Vizard explains how the enthusiast needs to shape the combustion chambers and smooth out ports for maximum performance. Of key importance, he shows how to optimize flow paths through the heads, past the valves, and into the combustion chamber. It covers blending the bowls, a most basic porting procedure, but it also covers pocket porting, porting the intake runners, and many advanced procedures. These advanced procedures include unshrouding valves, porting a shortside turn from the floor of the port down toward the valve seat, and developing the ideal port area and angle. All of these changes combine to produce…