For nearly 40 years Manley Performance has maintained a leadership role in the global motorsports community, supplying a myriad of valvetrain and internal engine components to enthusiasts, leading race teams, professional engine builders, specialty vehicle constructors as well as OEMs. With Manley Performance's NexTek Valve Springs, you will find no degradation of spring pressure in the later stages of a race. They are constructed from specially processed premium-grade chrome silicon that is virtually free of impurities or surface irregularities. The state-of-the-art winding, thermal treatment and finishing practices cannot be duplicated! NexTek series valve springs have been tested by leading engine builders who have confirmed them to be the best performing valve springs on the market today. These are a double spring with damper and can handle up to a max lift of .600"