Skunk2 Valve Springs are Coiled at a higher tension when compared to the Factory Valve Springs. Skunk2 Racing Valve Springs keep the Valves From Floating at High RPMs. Skunk2 Valve Springs are necessary when installing a Performance Camshaft or Turbo Kit.Skunk2 Valve Springs are Designed to be Used with Skunk2 Titanium Retainers. You can use Skunk2 Valve Springs with All Motor, Turbo/Supercharger or NOS Set Ups. Applications Below are Priced for a Complete Set of 16 Intake Springs and 16 Exhaust Springs (Inners and Outers). When installing Performance Valvetrain, always check spring compression and height before running the engine. Skunk2 Valve Springs are required with Skunk2 Stage I, II and III VTEC camshafts.If you would like to Use Skunk2 Valve Springs with other Types of Cams, please note the Following Specifications. Consult your Engine Builder to see if Skunk2 Valves Springs will work for your application.B Series Vtec (B16, B17, B18) - Part #311050350Seat Pressure 72lbs@ 1.300"Open Pressure 185lbs@ .400" LiftMax Lift .505"B Series (B18, B20) - Part #311050370Seat Pressure 61lbs@ 1.425"Open Pressure 210lbs@ .925" LiftMax Lift .500"D Series (D16) - Part #311050340Seat Pressure 35lbs@ 2.000"Open Pressure 170lbs@ .400" LiftMax Lift .470"H Series (H22) - Part #311050360Seat Pressure 100lbs@ 1.400"Open Pressure 240lbs@ .500" LiftMax Lift .530"