2000 mc ls engine noise

3.4 Tick or knock (some where in between), coming from engine. has alot of miles. had noise for over 5 yrs. obviously not a rod knock or would have blown up long ago. I thought was a lifter but just replaced them and noise still present. had heads off a couple yrs ago but noise not changed. Anyone have an idea of what is making noise? thankyou

The timing chain is another source of noise in these engines.

Piston slap?

Wrist pin?