Machine valve spring seats for proper installed spring height and spring cup fitment. Cutter bodies and pilots are interchangeable, Hardened pilots fit all 3/8 and ½ hand drills. Cutter: Cuts Spring Seat .625 ID x 1.565"-1.570 OD Cutter uses the following Pilots: 9025: Fits valve guides with 5/16" - 8mm valves, EVO & TC up to 2004, EVO Sportster '86-up 9026: Fits valve guides with 7mm valves, TC 2005 and newer 9027: Fits valve guides with 3/8" valves, Pan & Shovel 1948-1983 9024: Fits valve guides with 6mm valves, M8 17 and newer 9028: Fits valve guides with 11/32 valves Note: Special Order Product only. To order please contact your MCS sales representative. / Fitment: Cuts Spring Seat .625" x 1.565"