All vehicles covered by this guide are equipped with hydraulic lifters which are designed to automatically maintain zero valve lash. No periodic adjustments are required by this system. However, most of the vehicles utilize rocker arms which are retained by adjusting nuts. If the rocker arms and nuts are loosened or removed, then must be properly adjusted upon installation in order for the lifters to work. Because these adjustments are part of the valve train installation procedures, they can be found in of this guide.