Feuling Beehive High-Load Valve Springs For Screamin' Eagle Twin Cam Heads Features: Feuling High Load premium performance Beehive valve springs handle up to 750 lift camshafts These valve springs are made from premium stress relieved conical ovate wire with a nitrided surface heat treatment, shot-peened surface enhancements along with a Nano Peen polish They have an extremely high level of fatigue life and are designed to handle the highest demands of performance engines Dyno proven and track tested Kits include:Feuling High Load BeeHive valve springs, lightweight 10Titanium retainers manufactured from special Ti-17 alloy that are micro polished for enhanced fatigue life, machined heat treated chrome moly spring seats and valve locks and a set of premium Viton valve seals equipped with a spring loaded valve stem wiper system Spring pressures are 215 lb. at .585 lift, 200 lb. at .635 lift, and 185 lb. at .685 lift 10, 5/16 valve stem with standard keeper grooves and .530 diameter valve guides