Ticking valvetrain noise from fresh engine

I started a thread on here a few years ago with the same problem and got a lot of good responses but never found the problem. I have the same scenario with a roller block ( '89 360) with flat tappets and the noise seems to be drivers side near the front. I changed header gaskets 5 times tried 2 different cams (comp and lunati) and 3 sets of lifters and nothing ever changed. I am curious to see what you find.