Anyone performing power enhancing upgrades on their Ford 6.4L Powerstroke needs the ARP 250-4203 Head Studs. ARP 250-4203 Diesel Head Studs replace the OEM torque-to-yield fasteners with superior clamping power. Adding additional power to the 6.4L Powerstroke is easy, but the addition of power creates additional stress loads on the stock bolts that engineers never intended them to handle. There are no better cylinder head studs available then the ARP 250-4203 6.4L Powerstroke Diesel Head Stud Kit.