Intake & Exhaust Valves & Springs Ford 223 6 Cylinder Mercury (Valve Kit) Int Head Diameter: 1.780" Length: 5.110" Exh Head Diameter: 1.513" Length: 5.090" Int. Stem Diameter: 0.34195 Exh Stem Diameter: 0.3405" Spring Outside Diameter: 1.354""/1.374 Inside Diameter: 1.000""/1.020"