Increased cylinder pressures in the 5.8 required new, harder head bolts to maintain the clamping load on the cylinder head gasket. They reduce head lift an extra 6 to 7 microns. Still, the 5.8 head lifts more than the 5.4, so an upgraded MLS head gasket from Federal Mogul was required. The 5.4 gasket uses three active and one inert layer; the 5.8 gasket adds an extra active layer, the better to remain in simultaneous contact with block and head when high combustion loads are doing their best to separate them. The engineers say the extra gasket layer really helped.