Got it, but unfortunately mine is an f350 and has straight frame rails. The blocks will be the same dimension all the way down. Actually, the last mount at the rear is different being about an inch and a quarter lower. This mount is bolted to a frame extension that is peculiar to the f350 pickup. I made my extensions from square tubing and incorporated them into a trailer hitch that will be mated to a step bumper I plan to build later this fall. The top of my frame extensions are flush with the rest of the frame. Because of this, it looks like any wood blocks will need to be inch and a quarter. I am a cabinet and furniture maker and have about 10 boards of elm about 1 1/2" thick. Plenty to make blocks for anyone needing them. At this point, a side view of an f350 flareside might be just what I need, or ultimately a picture of the elusive 'frame extensions'. btw, I pulled the bed this afternoon. Like to get it right for tomorrow. Thanks