Crack in bellhousing

what do you supposed the cause of the crack was? Crack is at about 11:00 facing the bell? Is it at a bolt boss? How about a structural strap bolted over the crack? Just thinking no AWS D1.1 capable garage fixes here.....
More than likely the housing was bolted together to the block and something was in between the two or did the clutch come apart. It is a very strange crack after all these years. I’d put some technical data out there but it might overwhelm Pishta. Lol! :)