I have a stock 1980 258 Auto. Have been hearing a fairly loud pecking coming from under the valve cover. I took the cover off and started the motor to watch it. The #1 cylinders first rocker arms moved about half what they should. The #2 rocker arms moved very slightly if any at all. The 3-6 cylinders seemed fine. Does anyone have any ideas about what might be wrong and how to repair it? Any help would be greatly appreciated. Dave
While the engine is running push down on the pushrod end of the rocker arm. If it still doesn't move as much as the others you have a flattened cam lobe. Only cure is to replace the camshaft and ALL lifters. A fair amount of work, and a sign that it's time to consider an engine replacement or complete rebuild.