COMP Cams Elite Drag Race Dual Valve Springs are unlike any existing springs on the market. They feature a new proprietary, cutting-edge, progressive pitch coiling process from COMP that greatly improves durability and ensures safe spring life beyond traditional extreme-duty expectations. The COMP Cams Elite Drag Race Dual Valve Springs are smaller in diameter and feature higher frequencies. These new dual valve springs are coiled with a revolutionarily new process that enhances durability by engineering the outer spring precision to the interface with the inner spring. The Elite Drag Race Dual Valve Springs use a smaller, lighter retainer engineered with a newly developed and specially formulated spring steel. This exclusive design and use of lighter retainers substantially increases the longevity in extreme conditions, such as professional drag racing. Exclusive clean wire sourcing and precision micro-finishing are standard on every COMP Cams Drag Race Dual Valve Spring. Each individual spring is hand selected and matched with proper tolerance fitment between inner and outer springs. PartNumber : cca948-1 Description : Hi-Tech Drag Race Valve Springs; Single Piece Title : 948-1 Valve Spring, 1.650" Triple Assembly California Proposition 65 : WARNING: Cancer and Reproductive Harm P65Warnings.ca.gov Coil Bind Height : 1.13 Compatible .570" Guide Diameter Spring Seats : 4786-1 Compatible Retainer : 739-1 Compatible Shims : 4756 Compatible Spring Cup (O.D. Locator) : 4708-1 Damper : No Inner Spring Inside Diameter : 0.863/0.627 Number of Springs : 3 Outer Spring Inside Diameter : 1.196 Outer Spring Outside Diameter : 1.66 Seat Height : 2.1 Seat Pressure : 332 Spring Rate : 687 Valve Spring Series : Race Extreme Open Pressure(lbs) : 949 Outside Diameter(in) : 1.645 Camshaft Type : Mechanical Coil Bind Height(in) : 1.13 Open Height(in) : 1.2 Position : N/A Spring Type : Triple Inside Diameter(in) : 0.635 Installed Height(in) : 2.1 Spring Rate(lbs/in) : 686 Installed Pressure(lbs) : 332 Engine Components::Valve Springs, Retainers