New Z28 Springs, 2.02" & 1.6" Head Dia.Stainless Steel Valve Kit Chevy Small Block 400 350 327 (stock) INT. Head Diameter: 2.020" Swirl polished head with undercut stem. Exh.Head Diameter: 1.600" Swirl polished head with undercut stem. Both Valve Length: 4.910" Both Stem Diameter: 0.3415" (11/32") Stem Type: Chrome plated fully machined stem with undercut -1 Groove