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