Creating the flange for the Porsche 911 Carrera Exhaust needed unique designing from the beginning. The flanges for the design needed to have a specific countersunk system incorporated in them so they would match up exactly to the Exhaust Valves the car uses. Once the tube diameter and mounting bolt locations were accurately test fitted, the design had to go further with the final cuts by creating two specifically sized bolt holes to accommodate each sides exhaust valve mounting hardware.