LS2Swapped92

Kinda pulling my hair out at this point. Anyone have any idea what this sound could be?

Engine makes a clacking sound under these conditions:
- In park, acclerating part throttle between 2k-2.3k
- Driving,, light constant throttle 2.3k-2.9k


Engine does ***not** make this sound under these conditions:
- Driving, accelerating spiritedly
- Driving, decel, or engine braking
- Idling


Engine: LQ4 built at the end of 2015 brand new pistons, ls7 lifters, stock cam, new bearings everywhere. OP is normal.

Transmission: 4L80E swapped


What I've noticed:

- Rear exhaust manifold bolt was a little loose, using MLS gaskets,, tightened it down, didn't seem to have any effect.

- Drove car, immediately pulled valve covers today, pushed down on lifters, no play in any of them, all rocker bolts are tight, springs are not broken. No loss of power.

- Removed serp belt, noise still there

- Removed ac belt, noise still there

LS2Swapped92

Did a cylinder balance test, noise went away with #6 disabled. Pulled the pan, sure enough, the conn rod bearing is all galled up.

Wonder why that happened after only a year and a half of driving it