VALVE SEAT TOOL KIT. HIGH CARBON STEEL CUTTER. VINTAGE BLOCK HEADS HQ. Milling in the following sizes. At 45 DEGREE + 90 DEGREE. 1.3/16″, 1.1/4″, 1.5/16″, 1.7/16″, 1.1/2″, 15/8″, 1.3/4″, 1.7/8″. At 30 DEGREE + 90 DEGREE. 1.1/4″-1.1/2″, 1.3/4. 8 stem guide in the following sizes. 5/16″, 3/8″, 11/32″, 7/16″. 7MM, 8.5MM, 9MM, 10MM. Not suitable for Modern Engines hardened valve seats.