Valve spring kits are direct replacement no machining or rocker box clearance required Larger lift camshafts require valve guide machining for seal and retainer clearance Ti-valve locks, 10°, 5/16" standard height, fits Feuling high load BeeHive valve spring set upt Up to .574" lift for 1984-2004 Big Twin, 1986-2003 Sportster and up to .700" lift for 2005-13 Twin cam