batteries near the tank is a very bad idea, i wouldn't be surprised if it got you a nice big juicy fat fail at iva. there are now stricter rules about tanks and things that can affect tanks e.g sparks. a 12volt battery arcing out on the side of an ali tank will easily blow a hole in it.
i recall when i was younger accidentally touching a 13mm ring spanner between two battery terminals. the result was that the spanner ended up without the ring
my car has a pinto up front and at iva i was still heavier at the rear than the front. tbh with that boat anchor up front the weights wont be that far off 50/50 distribution.
be wise put the battery on the scuttle like it should be and don't kill yourself.