I am looking at locating my battery on the right frame rail behind the running board splash apron. I saw this set up at a Goodguys event last year on a 53. The running board splash apron was hinged at the top to allow access to the terminals. I think one of the battery drop down boxes was used but I plan to use the stock battery tray on mine. No pictures yet other than those in my head.

This will improve weight distribution and get rid of the floor access problem.