A sticky valve will cause erratic, intermittent noise due to the valve not seating all the way, and a bad miss due to low compression. Definitely check the cam lift at the pushrod side of the rocker arm. Harbor Freight and most of the other discount tool places have magnetic-base dial indicators at bargain prices, and I've had at least one of them as long as I can remember. Set up the indicator directly above the valve adjusting screw and check how far it moves as the engine is turned through two turns of the crankshaft. I like to use a piece of steel flat bar bolted to the head with the vale cover attaching holes to give the magnetic base a sturdy mounting surface. All the valves should move approximately the same distance, within a few thousandths. Intake and exhaust lift might not be the same, but all the intakes should be similar- - - -ditto for exhaust. If there's a noticeable lobe lift difference between cylinders it's time for a cam and lifter change.
Jerry
