Valve train noise.

A little background.. I have a 93LX with a low mile rebuilt shortblock. I added a set of rebuilt GT40 heads (comp springs, valve job, etc,) Explorer intake, B303 cam, and new FMS roller lifters. When I installed the stock rockers I put each valve on the base circle and was able to reach 20 ft/lbs at 3/4 turn past zero lash. Once the engine warms up I have a loud ticking sound from the top end. I am 99% positive it is not an exhaust leak. The car runs strong but once it gets up to temp the tick comes back. I pulled the valve covers and I do not notice anything. No witness marks on the VCs or anything. The rockers are still torqued correctly. I did notice that on a few rockers I can easily wiggle them around. Any ideas? I was hoping that I would see something blatantly wrong when I removed the VCs. However, everything looks good. It would be nice if I could get this issue resolved with one more try.

Yes, I spent I few minutes with a long screw driver to my ear. The noise seems to be coming from the front two cylinders on the drivers side. I have also done the same thing you described about 15 years ago with a 351 I built for my old step side ford. For that I actually took some old VCs and cut the top off. Of course that was a stud mount setup with poly locks and I was able to play with lash until it was quiet. On my 93 the upper intake gets in the way and would be a pain.