The ARP 230-4201 Head Stud Kit is a premium upgrade designed for 2001–2016 GM 6.6L Duramax (LB7, LLY, LBZ, LMM, LML) engines. Built from ARP2000 alloy and rated around 220,000 psi tensile strength, these studs provide significantly greater clamping force than factory torque-to-yield bolts.