I've got a 76 van that is showing signs of cracking around the pin area. also have a 96 g30(last year of that van body) that you can clearly see spot welds were it has a large backing plate welded in behind the pin area. I would definitely put a larger piece in behind those if you're very far...
you can get a 3.23 ratio for the 14bolt, but they are kinda hard to find. I don't think anyone makes it aftermarket, just have to find some original takeout gears.