SBC 350 top end noise

[eodbeast]

I have a top end tick that I can't find the cause of. Brand new Lunati cam (10120701), lifters and matching springs installed two weeks ago. No retainer/guide clearance issues, no coil bind, no retainer/rocker arm interference no rocker arm/valve cover contact, no collapsed lifters. Pulling 30 psi oil pressure at idle and 45-50 at cruise.

Valves have been adjusted 1/2 turn past zero lash, both static and while running with no difference. Replaced old stamped rocker arms with brand new OEM replacements and that took only a slight bit of the noise away...at least for a little while. I'm running Vortec heads on an older block. The same noise was there with the old stock heads, thought changing things out would quiet it down. Eliminated all belt driven accessories (alternator, water pump and power steering).

I'm at a loss and it's driving me nuts. Been turning wrenches on SBCs for 25+ years and have never had one stump me like this. Any ideas?

Here is a short video of what it sounds like.
http://youtu.be/B99cClzos1c