PAC 1509 HIGH NITRADED SPRINGS FOR HIGH LIFT AGGRESSIVE APPLICATIONSCALL SHANON AT 507 445 3235 WITH ANY QUESTIONS. 1500 series Offering an industry leading nitriding process that allow for the material to withstand the abusive wear and fatigue of the typical endurance engine environment. These springs come fully prepared for racing conditions with chamfering, polishing, and the latest surface enhancement technology available. From 24 hours of LeMans to the rigors of NASCAR the 1500 series spring has the history to