Has anyone actually broken a steering box?
I don't know how you would break one. The Flaming river manual box does have a cast iron case, vs the stock aluminum. I have seen one aluminum box that may have had a crack in the case. I don't know how it got there, and I think it was a casting flaw more than anything. But nonetheless I have welded up a aluminum cased steering box.
I think the bigger deal is the needle bearing set up on the shafts. The flaming river box uses needle bearings. The mopar boxes use bushings, except for some of the B-body V8 boxes which used bearings. I don't think that would improve the strength much if any, but they would wear better.
Steering Box Info
What I don't know is if the new OE look boxes that are being sold by PST and others have bearings or bushings. Maybe
@PST will chime in