Tonight I cut out the old spare tire carrier under the rear of the van. It was not as heavy as it looked. I raised the storage box up into place for a test fit, before I fiberglass the outside. It needed trimming so I took it apart and narrowed it by 3/4" It fit before, but would not have fit after fiberglass- I guess I got a little carried away with the overall dimensions. after ripping down the width of the box, I jacked it back up into place. It fits good now except I'm not sure about the depth. It will go up about 1 1/2" more than in the picture (after I cut out the van floor).
Even though I measured before I built the box, it seems shockingly low seeing it in place. Any one have a picture of theirs installed? Or a measurement?
It looks like a couple of bolts through the sides of the box and through the side supports of the reese hitch would be easy additions to my original plan.