I have about a half mile of thick wall 2" angle iron(bought at a yard sale of all places. New, it was a pipe dream of someone trying to buy their idiot son a job) here and will build the battery boxes starting this month including the engine battery new mount.
There's a coach floor metal support that runs right along the top of the Ford frame, just on the outside of those bongo bins(someone else's name for them that I've adopted. With the two bins and the bass tone channel between them, they're like a set of bongos).
I'll hang the battery box on them and tie to the ford frame hopefully using the exisitng bolts in my rear spring hanger.
After buildng and designing the first set, the next ones will be jigged and welded in about half an hour.
Maybe I'll have a second set finished in time for the spring meet
They'll bolt in, no welding to the Thor.