I'll go with Larry that your carburetor has been modified. Ford 2100/4100 carburetors had vertical choke link seals in their designs. There is a felt shaft seal or gasket that provides some sealing (keeps big debris out) the large oval passage in the carburetor body. Low pressure inside the air cleaner/ carburetor upper end would pull the seal through the large oval hole so there is a thin brass retainer to cover much of the large oval passage. All the parts are free to easily move laterally.
Carburetors with damaged or missing link seals are very common. Here's some images from a new old stock HP289 specific 4100 model.
