Stop in for a cup of coffee

So. Ihc is still running hot.
Decided to try a different rad. Have one from a 52 chevy 1 ton.
A little trimming and it fits.
As i was moving it around i heard something clanking inside the rad. View attachment 1715359514How dat get in dere???
3/4 proto socket.
WTF? Someone tried a redneck flow reducer?