Hi,
You followed the correct procedure. The valves are adjusted too tight if your engine runs rough. What happens is the lifters bleed down and loose their
oil pressure, this makes it seem like the valves are adjusted too loose as the pushrods will turn. An easier way to adjust the valves is to pull out all the spark plugs. Turn the engine over by hand with a socket and wrench on the front crank bolt. Have someone stick their finger over the cylinder you want to adjust[follow firing order] When air rushes out and stops,that cylinder is at top and on the firing stroke, = both valves closed. NOW you can adjust both intake and exhaust valves. loosen off the rocker adjusting nut until there is a noticible clearance on the pushrod. Slowly tighten it until there is no up and down clearance. Now give it 1/2 turn more to set preload and lock nut.
Perry.