Those engine are known to throw rocker arm/cam followers off.Get a new lifter and follower(rocker arm).install.Parts have been updated.Most likely exhaust side.Overhead cam so the rocker/follower sits right under the camshaft and pivots off the lifter.basicly just pry the new follower in place.PAY attention and don't mark-up the cam surface.The valve cover gasket is reuasable,so try not to tear it when removing the cover.Pricey gasket.$40-$50?.Been a while since I bought one though.Valve cover is gonna take a while to get off.Not no 1/2 job.First time,expect 3 hours or more for the whole job.make it easyier,just remove the battery tray,and the heater hoses.trying short cuts will just cost you time.