I hear lotsa noises;
All those already mentioned,and
I really think I might be hearing a rod in there.
Slow the engine down to 700 or less if it will go there. Then saw on the throttle arm ever so slightly. If it's a rod, then every time the rod is unloaded, it will hammer. So, the sound will not be there when you open the throttle, but the millisecond you are backing off the throttle;knock-knock, there it will be. And then it will be gone. That is how they (rod-knocks) have always started for me.
This stage does not usually last long.:(