Ticking valvetrain noise from fresh engine

Thanks for your support!

I did check the valve´s installed height with a straigth edge, they were dead even.
Yes it´s a flat tappet cam :-)
The valve covers were removed for inspection and the engine was run with cardboard splash shields, no interference there...

Talked to an engine guy and he came up with this:

Running a flat tappet in a roller block, maybe some of the holes feeding oil from the galley to the tappets dont allow enough oil to enter the lifter. I´m using cheap summit lifters, maybe the groove in them is to high above the lifter´s face?

I´ll try to take and upload a video or audio file.

Thanks so much
Chris