No, i ended up manufacturing brackets that slide up inside the bottom of the seat, those are then bolted to the sliders which in turn are bolted to the floor using additional brackets.
But my setup is slightly different than a regular E-350 van. Mine is an RV, an E-350 cutaway, theres a transition edge that sticks up about 1.5" inches behind the seats where the floor transitions into the living area. The brackets i made that go inside the seat are all one piece and of course you have to make sure the slider doesnt interfere with the seat recline mechanism ect.... and of course the seat is offset so that has to be accounted for. It took me a couple days of piddling around with it on and off to decide on a good way to make the seat brackets. I didnt feel confident just bolting a couple chunks of angle under the seats even though im sure that would accomplish the same thing and be just as effective.
I have all the brackets made already but i still have to install the passenger side. I can snap some pics when i assemble it and post them here. I just havent been feeling the greatest for about a week now so i havent got much accomplished.
If you only knew.