Here's the thing. This is a simple piece to make. All I did was cut off a piece of tubing with a large enough ID to allow the large shaft/bolt to clear through it. Then I welded on a thick washer onto the bottom. This piece was then put into place. Then I cut off a piece of 1/4" steel flat bar 11/2 inch wide and long enough so that the piece of tubing would clear the bolt head that secures the chassis brace. Once both pieces are in place a piece of 5/8 diameter thick wall (I think I used .125) tubing was cut to fit between the two and then tack welded in place. Then the assembly was removed from place and finish tig welded, painted, and put in final placement.
If you don't have a welder then make all the pieces, mark carefully, and have it done. As far a cad files go all you need is a hack saw and a electric drill.
Note: do each side independently to allow for variations.