Then you are talking about the cup that goes on the bell housing (not the starter)51.. I don't need the band.. I need the (lets call it) the end cap, where the starter drive spring end would be.
If you have the 4-speed or an 11-inch clutch, the cast iron half bell has a metal cap on the back of the starter opening that can get damaged or fall out. You can rig a PCV pipe cap on there but you might have to get the whole casting to get the OEM metal cover. It's just a press fit in the housing.