[Eljaro]

Brent,
I had a similar problem with valve lash inconsistent adjustment, and it was the pushrods which were touching the holes in the intake manifold. So I would adjust the lash , actually bending the rod against the side of the hole in the intake manifold. The pushrods would end up bending or wearing off the aluminum in the intake manifold holes, or wearing off the cup against the ball at the top. Next time around the lash adjustment was off on many of them.
When I got a new intake manifold (Edelbrock Performer RPM) I had to grind every one of the holes to prevent pusrod contact with them.
You can see that by yourself in a minute.Take the valve cover off, turn the engine over and see if you can turn the pushrods by hand and see if they rub against the hole in the intake manifold.
Just a suggestion, after everything else seems to be ok. in your engine.
Good luck!