More on trying to remove a 47 DeSoto crossmember.
I had the floor panel out to make a small part of it removable where I added a mechanical brake switch and a Jiffy-Jet pump. (Tough to get at those items.) I took some photos.
Here is the cutout, for access to the switch and pump:
The master cylinder bracket is riveted at the back to the frame, welded to the crossmember, and welded to the top of the frame.
To remove the crossmember, it may be simpler to cut the bracket free of the crossmember and leave the bracket and MC in place.
So maybe I'll try jacking up the motor and bell housing, as discussed, to replace the rear motor mounts, next Spring or whenever.