What's the possibility the engine has been swapped for one with hydraulic lifters? Have you done any research on the numbers stamped on the machined pad behind the distributor? If the valves are actually that tight, the engine would be running really lousy (or not at all) if it has solid lifters. Hydraulics run at a "zero lash" situation because the lifters are pre-loaded during their initial adjustment.
Try this- - - -Using a pry bar or a long screwdriver, and apply a firm pressure to one of the #1 cylinder rocker arms like you were trying to force the pushrod down into the engine. If a gap appears between the tip of the rocker and the valve stem after holding the pressure for 2-3 minutes and eventually goes to 1/8" or so, you've got hydraulic lifters. If there's no change at the rocker tip after a couple of minutes of constant pressure, the engine has solid lifters.
Good catch, Shaker! The feeler gauge needs to go between the valve stem (with the spring around it) and the tip of the rocker arm, on the opposite end of the rocker from the pushrod!
Jerry
