Sorry to hear about all your troubles Terrance, having been down similar roads, I remember all too well how frustrating it can be.

As I read thru your story it sounds like you have replaced everything at least once and sometimes twice and nothing has effected the sound.
Given all the issues you've had with the rebuild, it does sound as though they may have taken a short cut here and there (AM h/g...)

I did note that you said the engine shop replaced the camshaft already?
Is there any possibility they used either the wrong cam (3Y vs 4Y, don't know if theres a difference or not) or possibly put in a regrind??
Back in my speed shop days, there weren't a lot of performance cams available and those that were available were incredibly spendy.
We often had cams reground and while some worked out sweet as pie others had excessive valve noise.

Given how far you've gone on this, it might be worth finding out what they put in, even if just to eliminate one more possibility.
BB