This listing is for a brand new high performance cylinder head parts kit that comes with stainless steel intake and exhaust valves, Z28 style performance valve springs, heat treated spring retainers and heat treated valve locks. Kit Includes: (8) 1.94" Stainless steel intake valves. (8) 1.5" Stainless steel exhaust valves. (16) Stock diameter Z28 style valve springs. (16) Heat treated 7° valve spring retainers. (32) Heat treated 7° valve locks. This kit will fit many 1955-1993 small block Chevy 302, 307, 327, 350 and 400 V8 cylinder heads and also could fit many cast iron and aluminum aftermarket heads depending on the valve head diameter and length you need for your application. The Z28 springs are stock outside diameter and can be used as a drop-in fit in many 1955-1993 small block Chevy V8 cast iron cylinder heads. They work great for stock, towing and most mild performance cams and work best with cams up to 0.500" lift. Intake Valves: Forged one piece 21-4N stainless with hardened tip Head Diameter: 1.940" Swirl polished head with undercut stem. Valve Length: 4.910" Tip length: 0.250" Stem Diameter: 0.3415" (11/32") Stem Type: Chrome plated fully machined stem with undercut 1 Groove Exhaust are: Forged one piece 21-4N stainless with hardened tip. Head Diameter: 1.500" Swirl polished head with undercut stem. Valve Length: 4.910" Tip length: 0.250" Stem Diameter: 0.3415" (11/32") Stem Type: Chrome plated fully machined stem with undercut -1 Groove. 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. (8)53-100194 (8)53-100150 (16)RV943X (1)EHC-555R (16) 55-6100