Is this for dragstrip racing,where you'll need a master disconnect switch at the rear that's easily accessable to shut the truck down in the event of a crash? If not,it's easy just extend your battery cables,i use 00 welding cable,and put the batteries where you want.I'm not sure how to incorporate a master disconnect switch on a 3rd gen Cummins,but on a 4th Gen gasser you need the master disconnect switch to not only shut off battery power,but it also has to kill power to the fuse box. With-out killing alternator power to the fuse box,a gasser will stay running,i don't know if a Cummins is the same way,as it doesn't employ spark plugs,so it might stay running unless the fuel is cut off.
Back box is relocated battery,front box is the stand alone fuel cell dedicated to the nitrous side of things.
My battery is in a NHRA legal Taylor battery box