Ditto what Debo said
. The batteries are up front for a couple of reasons - balancing weight, reduced heat and vibration, close to the large "house" loads of the air conditioning and heating systems, and in a converted bus the house batteries and inverter. Some do move them, and put the house batteries in their place, retaining the 4/0 cable that runs up to the front bay from the engine compartment to feed the bus loads and charge the house batteries. The advantage of putting the batteries in the rear are freeing up the space in the stock compartment for other batteries, and a slightly shorter cable to the starter motor will in theory allow more amps to the motor - in theory only because that only comes into play when the battery is reaching a limit on amperage output.