Looks a lot like the K&B .40 rods I mentioned...whupped!
Over-heated... maybe by too much prop, and too lean?

The bottom end looks like either it has remnants of a bushing, but it might also be (no bushing ) just discoloration from varnish and or a little rust residue in the chamfer?

You can also see where the top end of the rod was rubbing the pin bore's boss in the piston...must have been fore/aft thrust loads...it may be a slightly bent rod too, or just rocking caused by the wallowed out hole?