Originally Posted by Salty9
As a WAS use aluminum sheet to make a cover to fit the bell housing and sandwich it between the adapter and bell housing. Of course, you would have to use appropriate sealing material.
Why would you want to seal it?
Most bellhousings are effectively open - you normally have a telltale hole at the bottom specifically to let the oil out if an engine or gearbox seal leaks
Just to warn you that you have a problem
You don't want pebbles in there! but otherwise why worry?