Ferrea Competition Plus +1mm Intake Valve Set of 12Ferrea Competition Plus intake valves have built a reputation as the industry's most reliable extreme duty valve. To manufacture the valves we use special aerospace quality alloys, including the EV8 Z18, which provides high tensile strength. An exclusive two step slow forging process ensures proper grain flow and virtually eliminates any damage to the material structure. The valves are then heat treated and stress relieved over a 48 hour period, which