Lifter noise

I have a 97 wrangler, 4.0, 70k miles. Have what appears to be a lifter noise. Removed valve cover, pushed on valves. When pushed on No. 6 exhaust valve the noise went away. Replaced all the lifters. Same noise, same place. Swapped push rods and rocker arms. But the noise stays in the same place. Had the exhaust manifold out and welded 6 months ago. If I push on the valve while running, the noise goes away. Any ideas what to do next?

Pushing on the valve? That might be your problem, might be a worn valve seal or problem with the spring.

Sounds like you've changed everything else in the valvetrain (except the cam, but doubt it's coming from there)