A simple way to solve that problem is remove the rear most bracket for the battery tray on the frame, drill new holes in the frame and bolt it back on a few inches farther back.
while you're at it you need to make a new bottom, but the original is probably rusty or mostly gone by now?
If you want to you can also straighten the flanges on the bottom of the battery tray brackets so the bottom is then lower and accepts a taller battery.
Another idea is to hinge the bottom so the battery can be removed from underneath as it will be a tight squeeze out the top.
I used all these methods on my 52 1 ton and fit a larger 12V battery.
Another option is many of the vendors and hod rod places sell drop down battery boxes to replace the original.
Grigg
