Brent go back to the beginning and check the basics valve spring binding, oiling to the pushrods, ck for blueing, binding of the rocker body to the pushrod, you have the oiling holes facing down? What heads and block do you have. What head gaskets are on it? Size of cam? When the motor gets hot you may have spring binding and bottoming out the rocker. Does the clearance disappear after the motor cools down of great larger, or stay the same??? Need some answers please.
Maybe the motor doesn't like Calif. or the govennor choises.
Rick Lake