Cuts Spring Seat .550 ID x 1.180 - 1.185 OD. Used to cut spring seats for proper installed spring height and spring cup fitment. Cutter bodies and pilots are interchangeable. The hardened pilots fit all 3/8" and 1/2" hand drills. This cutter is designed for M8 cylinder heads using high lift camshafts. See Feuling M8 valve spring kits #993530 (565" lift, re-use upper spring collars) , 588021 (.565" lift, with titanium upper spring collars), 588022 (.600" lift). Note: The M8 cylinder head material under the valve spring seat pocket to the top side of the exhaust port is fairly thin even more so on ported cylinder heads. Cutter uses the following Pilots: 707265 Fits valve guides with 3/8" ( 9.53mm) valve stem, 48-83 Pan & Shovel 707263 Fits valve guides with 5/16" (7.9375mm) valve stem, 84-99 Evo; 99-04Twin Cam and 86-22 Evo XL 707264 Fits valve guides with 7mm valve stem, 05-17 Twin Cam 707262 Fits valve guides with 6mm valve stem, 17-up M8 707266 Fits valve guides with 11/32" (7.7313mm) valve stem Note: Special Order Product only. To order please contact your MCS sales representative.