It's a machined part (not cast), so I would say if it's not part of a lifter, it could be part of the oil pump (like where the pickup tube goes in). Just a guess though.
You stated you previously pulled the pan. What was the reason for it, and what did you do when it was down. Any other engine mods since then....?
You stated you previously pulled the pan. What was the reason for it, and what did you do when it was down. Any other engine mods since then....?