The ARP 247-4205 Custom Age 625+ Head Stud Kit is built to keep your 12-valve Cummins sealed under pressure, delivering the clamping force needed to help prevent head lift and gasket failure in high-boost and heavy-use applications. Designed for 1989–1998 5.9L Cummins 12V engines, these studs are manufactured from ARP’s Custom Age 625+ material for exceptional strength, fatigue resistance, and consistent clamping in demanding conditions.