Model A pickup bed new floor made to clear the step up in the chassis for the Jag rear diff.  The pictures in the gallery above show more details. An example of my metal working skills, making this Model A ute bed fit the custom Model AA Truck chassis I built. It runs a jag rear and the truck sits really low, so the step up at the back is substantial. However it only protruded into the ute bed by around a 100mm or so. Rather than lift the hole floor in the ute tray, I thought for this one just have a step in the floor that hugs the chassis.
   
The opening in the middle is for access to the bolts that hold the diff centre to the chassis, you will see a nice cover in the top photo of this. The step up required some frame made from RHS, just to be sure if some clown decided to jump up and down on it that it would not buckle in.  If the step was done in the same ribbed style as the floor it would add complexity in mateing up the corners of the step up. It would also make the step up look more cumbersome, I decided this looked neater and was kinder to the custmers budget.