Our Billet back plates use advanced CFD simulation and exacting 3D precision milling to create a blend of engineering and manufacturing that produces less leak by, less aeration, less cavitation, and more high RPM flow. Plate is cut from billet steel, 5 times as rigid as aluminum, reducing blow by and air ingestion. Plates feature our MartenWear surfaces for long life. Increased volume and reduced foam increase engine bearing life. Utilizes surface grinding to create the ultimate pump seal.Includes high-pressure o-ring seal to eliminate leaks.