Made from premium stress-relieved conical ovate wire 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 demands of performance engines with 585″ and smaller lift camshafts Kits include: Econo BeeHive? valve springs, lightweight 7? steel retainers, 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; 183 lbs. at 1.770″ (0.510″ lift), 175 lbs. at 1.795″ (0.535″ lift), 172 lbs. at 1.813″ (0.553″ lift), 165 lbs. at 1.835″ (0.574″ lift), 160 lbs. at 1.845″ (0.585″ lift), 380 lbs. at 1.260″ OPEN HEIGHT coil bind at 1.190″ 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. Econo BeeHive? kits are direct replacement with no machining or rocker box clearance required for cams up to .574″ lift for 84-04 Big Twin and 86-03 XL and up to .585″ lift for 05-17 Twin Cam.