Fresh engine, wiped cam? Tick? (new pics added)
the lifter is hyd...it may feel solid becuse there is oil in it, oil does not compress. Your valves have many pounds of pressure on them, at least 90 with the valve closed.
you are already pulling the intake?
have you checked your pushrods for straitness like I said?
did you check to see if they were rotating when it was running?