Before removing the valve cover, you need to take of the rocker arm stud nut or bolt with the fulcrum seat and rocker arm for each cylinder and it is advisable that you arrange them in a manner that you can recognize them or label them so that you can return them in their respective place when doing reassembling. Go through the general condition of the rocker arms, with special attention to the areas that touch the valve and the pushrod. Regarding pushrod pull, they must be pulled upwards through the Cylinder head and out of the lifter pocket, pushrod directly through the cylinder head: As much as is possible keep them assembled and aligned or make a sequence arrangement of the above and put them in a cardboard box to avoid misplacing them. Look at the pushrods after they have been removed. For installation, use engine oil or assembly lube to the top of the valve stem, and to the rocker arm fulcrum seat, intended as well as the socket. Slip on the pushrod with some lubrication applied at both ends, and then the fulcrum guide, rocker arm, fulcrum seat and then fasten it with the stud nut of bolt tight to the required torque. If any of the components needed replacing then check the valve clearance and make necessary changes in the length of the pushrod and then refit the valve cover and gasket.