On the advice and suggestions of several experienced members, I took a spare '70 B body K member and went to work on it. In this picture you will notice a long screwdriver that points to what WAS an open, unsupported area of the steering box mount.
You can also see the washers welded around the lower control arm pivot shaft holes. These washers are 1/8" thick and spread the load of the LCA to a much wider area. I have seen several K members that were damaged in this area when the thin factory weld breaks loose and the hole elongates.