Stretched Head bolts can lead to blown head gaskets and overheated engines. Head Studs offer a alternative when its time to reseal a engine head. Bolts when torqued are affected by two difference forces. The bolt stretches and twists. A Headstud will not twist as only the nut is torqued down. This allows them to add more clamping force and helps reduce the chance of burning up a gasket Fit 04-10 Ford E-350 04-10 Ford E-450 03-05 Ford Excursion 03-07 Ford F-250 Super Duty 03-07 Ford F-350 Super Duty 03-07 Ford F-450 Super Duty 03-07 Ford F-550 Super Duty 03-10 Ford 6.0L Powerstroke Diesel Head Studs