Don, the profile is non standard it is 30mmx20mm. The end plates are not square, they are skewed none the less the longer side is 87mm. top and bottom match the frame rail in my case 30mm, the angled sides are 30mm and inboard side is 30mm (matching the cross brace) The threadnut is 370 mm from the left frame rail.
I'll have to get back to you on the thread of the threadnut.