Spring Kit – .660″ – Evolution/Twin Cam

Stainless steel conversion kit includes only what’s needed to convert your head to the long-life stainless steel Black Diamond™ intake valves; Extend the life of the valvetrain and intake components by as much as 4x over the OEM titanium parts; Includes forged one-piece stainless steel intake valves, wound chrome-silicon heat-treated wire valve springs, ultra-light titanium retainers and hardened steel bases; Components are created using Finite Element Analysis (F.E.A.) software, as well as proprietary camshaft analysis and spring design software; Specifically designed and engineered for each application; Made in the U.S.A.