Valve Train Noise

Hey all,

I need helping pin pointing a valve train noise.

Had 3 runs down the ¼ mile and coming off the last run I heard a slight rocker noise when the revs dropped

My engine builder says it definitely sounds like a loose rocker
The lash in the rockers have not moved, but we have adjusted them 4 times just to make sure both hot and cold.
It only makes the noise under light load over 2000rpm

I have been street driving this for the last 18 months with no issues
Oil pressure is good. 75psi cold, 40psi hot at idle

416 CI
SFT comp cam 256/265
Ported eddy heads
Hughes 1.6 rockers
Johnson solid lifters
Plenty of oil to the top end