68 Barracuda 340 water pump , timing cover question ???

Most likely the elastomer ring has let loose in the crank damper allowing the outer ring to move and hit your timing cover. Your damper is now junk as there is no relaible way to rebuild it.
The front of your engine is known in the Mopar world as a pre 1970 configuration.
You will need to source a direct stock replacement damper as the after market does not offer a fancy SFI rated piece for a pre 1970 that has the correct timing mark location.
Good luck