PAC-1237X-16 0.630 in. ID – 1.274 in. OD – 1.800 in. installed Height – 0.700 in. Max Valve Lift

0.630 in. ID – 1.274 in. OD – 1.800 in. installed Height – 0.700 in. Max Valve Lift PAC Racing’s RPM Series Dual Valve Springs are constructed using our signature PACaloy super clean wire and are heat-treated in-house for precision spring rates and improved strength. They also receive a multi-peen process, polishing, and a Nano-Peen™ proprietary surface treatment for service life optimization. These springs fit GM Gen III/IV LS engines with specific part numbers for stock heads and aftermarket heads. Built using our signature PACaloy super clean wire to ensure strength and durability In-house heat-treating for precise spring rates and increased strength Multi-peen process to optimize service life Polishing to improve operating cycles Nano-Peen™ proprietary surface treatment Outer Diameter – Outer Valve Spring 1.274 IN Inner Diameter – Outer Valve Spring 0.900 IN Inner Diameter – Inner Valve Spring 0.630 IN Installed Height 1.800 IN Installed Load / Height (Valve Closed) 200 LB @ 1.800 IN Open Height 1.100 IN Open Load 585 PS Open Load / Height (Valve Open) 585 LB @ 1.100 IN Valve Spring Rate 550 PS Max Coil Bind 1.045 IN Max Valve Lift 0.700 IN Recommended Valve Spring Retainer – 400 Series R432 Recommended Valve Spring Retainer – 500 Series R532 Recommended Valve Spring Retainer – 600 Series R632 Recommended Valve Spring Seat S128, S138 Valve Spring Series RPM Series Valve Spring Type Dual Primary Market Circle Track Drag Race Street Performance