Dual Valve Springs Stahl Retainer LS2 Modulars Helmets Brian Tooley Racing (BTR) Platinum .660 Dual Valve Spring Kit For LS Engines (LS1, LS2, LS3, LQ4, LQ9) Intake Manifolds For LS1 Brian Tooley 660 Spring Kit Brand: Brian Tooley Racing Manufacturer Part Number: SK001S Country/Region of Manufacture: United States, Material: Steel