I have never heard of using the bellhousing to bolt an engine to an engine stand before
How many stovebolt engines have you rebuilt? The bellhousing on a 216/235/261 has some bolts attaching it to the block that are hidden by the flywheel once it's installed. It's not uncommon to install the bellhousing (which is heavy cast iron, BTW) then install the flywheel and clutch assembly, and remount it on a stand for the installation of the manifolds, water pump, etc. If it's done properly, with a sufficently strong (and long) engine stand, no problem. The danger is in trusting overly optimistic "weight ratings" dreamed up by some advertising copy writer.
"Ignorance can be fixed- - - -Stupid is forever!"
Jerry