There was just enough room to shoehorn the batteries between the chassis and the front drive shaft.
Because I bought 2 Optima (maintenance free) batteries, I could position them in this "hard to get" position. An added benefit is to lower the center of gravity by having them so low.
The rack is bolted on one side to the frame and suspended on the other side by a long 10 mm threaded bar.
When constructed and before the final coat of paint, I fitted the rack to the truck to make sure all is well!
=> Perfect fit ! GREAT !