Help! Small block 360 has a knocking sound

ok, what do you suggest I look for? I have pulled the valve covers and watched it run, and everything is oiled and working just fine. No bent push rods, nothing was loose, all valves are opening and closing just fine.
Those are all things I would have looked for
Stock rockers?
Hydraulic lifters?
No signs of excessive wear on the rocker shafts?