Fresh engine, wiped cam? Tick? (new pics added)
Didn't read all the posts, don't know if its been mentioned...
I have had a broken valve spring (even one of the inner dampeners) make some racket and tick especially in the RPM's. Without noticeable effect on performance. I would get a good light and take a close look at all of the springs, inners & outters... Just a thought.
JOE