Made from premium stress-relieved conical ovate wire with nitrided surface heat treatment, shot-peened surface enhancements and Nano Peen? polish Feature extremely high level of fatigue life Use a much smaller and lighter weight retainer to reduce valve weight and create quicker rev and smoother motion Designed to handle the highest demands of performance engines with high-lift, steep-ramped camshafts Kits include: High-Load BeeHive? valve springs, lightweight 10? Titanium retainers manufactured from Ti-17 alloy and micropolished for enhanced fatigue life, machined heat-treated chromoly spring seats, seat shims, valve locks and a set of premium Viton? valve seals equipped with spring-loaded valve stem wiper system Seat lbs./installed height; 217 lbs. at 1.789″ (.574″ lift), 215 lbs. at 1.800″ (.585″ lift), 208 lbs. at 1.819″ (.604″ lift), 200 lbs. at 1.845″ (.630″ lift), 185 lbs. at 1.900″ (.685″ lift), 170 lbs. at 1.935″ (.720″ lift), 415 lbs. at 1.215″ (open height) coil bind at 1.125″ Dyno proven and track tested Feuling? BeeHive? valve springs must be installed at the correct OPEN HEIGHT, matching max lift to the open height spec of the valve springs Made in the U.S.A. Feuling? BeeHive? valve spring kits are direct replacement with no machining or rocker box clearance required up to .574″ lift for 84-04 Big Twin and 86-03 XL and up to .700″ lift for 05-17 Twin Cam. Larger camshafts require valve guide machining for seal-to-retainer clearance.