So he has
But my truck, my sweat and money, my way. I have purposely made some decisions that lean towards daily driver and away from show car. I know I'll only enjoy this thing if I use it and I'll only use it if it is reliable and it will only stay reliable if I make it easy to work on.
So engine bay mounted battery it is. Then there two choices I see, firewall near heater or inner fender as tempest did. One of the reasons I chose firewall was to leave option for mounting an ECU under the battery box in future if I ditch the carb for EFI.
I don't expect my battery to leak and I'd rather see it if it does. The worst battery messes I have seen were the batteries that are out of sight - under rear seat, under floor or under some plastic covered box.