So how does this work?

No.....dont throw it out. the hemi four speeds also used the big retainer. There were three sizes I believe. Some transmissions ( hemi 4 speeds and od 4 speeds ) both use the larger, beefier input bearing necesitating the larger retainer. I cant see in the pictures, how many splines are on the input shaft? 18 means it is a hemi box, or has hemi internals. 23 means is is an od or regular 4 speed.