Wow, great info!! For some reason that seems different from what I remember (still kicking myself for not measuring the blocks before I delivered the short box). I've attached a sketch of what I remember about the block mounting arrangement. I can see that you got both the blocks on the rear that fit in that 'U' channel. The rest I am confused about. I have also attached a blow up of the box I delivered showing the wooden block on the front of the box. I would appreciate it if you would look at these and comment. Again, thanks for crawling under your truck on a Sunday.