Another engine knock question.

The Jeep has never knocked before this spring. Over the winter I adjusted the valve lash, reinstalled a PCV system (the old one was plugged off), installed a stock air cleaner system and plumbed the intake-to-dipstick tube hose which had previously beed capped off, istalled  new plugs, wires, cap and rotor, replaced the fuel pump and installed a fuel pressure regulator. New intake and exhaust gaskets. After all that I didn't run the Jeep till this spring. When I did, I got a knock that was never there before.

*The knock doesn't begin till the engine gets warm.

*It seems to go away at RMPs above idle, and returns when the RPMs return to idle.

*Oil pressure is 60 cold, 20 hot at idle rising as high as 60 with increased RPMs.

*Using the screwdriver "stethescope" I am unable to isolate a location for the knock.

*Disconnecting one plug wire are a time has no noticable effect on the knock other than to slow it down as idle RPMs drop with the loss of the cylinder.

Wouldn't a bad main bearing result in a loss of oil pressure? A bad rod bearing continue to knock with an increase in RPMs? What do you guys think? Have a listen in the video below.

Your knock doesn't sound quite as severe as mine, Could be a chunk of carbon, or some debris that broke free when you replaced the manifold.  Or it could be something else entirely.