Knocking 340

If it is a heavy, low pitched knock, then likely a rod bearing, possibly a piston pin. If a high pitched knock, then likely a lifter. Both fixable.... just takes 'Pounds'. (No more Euro's for you guys, right?!)

>040" overbore may not safely allow any more overboring. Might.. might not. You can't know until it is torn down and the cylinder walls sonic checked.
I would probably pull engine and pan to investigate the issue if that’s possible after ruling out a lifter problem. Not what you want to hear I’m sure. Could be an oil pump giving out. I’ve had that happen.