This listing is for a brand new cylinder head parts kit that comes with stock style valves with chrome plated stems, 11/32" Rubber Positive Valve Stem Seals, Z28 style performance valve springs,Stock Push rods Overall length: 7.793", hardened spring retainers and hardened valve locks that are made by Elgin Industries (Elgin, IL USA). This kit can be used as stock or with an upgraded RV camshaft. These Z28 springs are stock outside diameter and can be used as a drop-in fit and are compatible replacements for many 1955-1993 small block Chevy V8 cast iron cylinder heads. Springs are: Outside Diameter: 1.260", Inside Diameter: 0.785", Closed: 114 lbs. @ 1.710", Open: 318 lbs. @1.210", Coil Bind @: 1.160", Spring Type: Single with damper. Intake valves are: Intake Valves are over all Length: 4.880" & 1.940" Head Diameter. Exhaust vales are over all Valve Length: 4.923" & 1.500" head diameter. Both have 11/32" (.341") stem diameters and 2 Groove - Chrome Plated stems. Part # I-408B x 8 + E-1923B x 8 + RV-943X x 16 + 55-6100 x 16 + VS-305V x 16 + PR-34B x 16 + EHC-555R + RK401 x 16