Thanks Duke. The box blade is apparently some reproduction of the #40 IH model. I don't have measurements for that blade, but this one matches up very closely visually. The obvious differences are the lack of a separate bolted on back blade (this one has a welded arched piece of steel) and that the crossbar is welded on rather than the U-clamp style attach. (I missed on a #40 last month for $200
) No matter, this one is very close, works perfect with the Cub and was $50.
I was able to modify it to fit the wide-frame 3-point of the 882 by drilling just 5 holes, so no major hack job that can't be undone.