How old of an engine? Bottom end knock er top end tick? If its bottom end I would drop the pan and at least make sure all the rods and mains are tight to spec. If they plastiguaged the bearings they could have forgot to tighten one er more of em. Unless its pinging from detonation and thats what ur hearing it is probably something else. If its top end check valve tollerances.
Noises are hard to diagnose by remote control. Does it make the sound all the time and all speeds? Is the sound soft or sharp? Deep heavy metal clunk, light tap, or somewhere in-between?
To help with info, get a stethoscope, or chunk of garden hose, or long screwdriver or broomstick and put it to your ear, moving the other end around on the engine to pinpoint the source as close as possible. Let us know what you find. Diagnosis before disassembly. A bit more known history of the engine may also be helpful.
PS: If it makes you feel better, the last knocking engine I had was a loose harmonic balancer. One bolt re-tightened and the knock was gone. Hopefully yours is similarly simple.