Adding a transfer tank is not too difficult and very affordable.
I had to cut the fill tube and add a few inches of height.
Crossmembers:
Lots of drilling , painting and welding...
The tank hangs just below the frame rails.
All plumbed to the tank-
Pump line tee'd into the main tank fill vent line and the tank vent tied into the main tank vent line-
My fiberglass traction/bridging ladders act as a shield for the tank, held up by winches mounted on either side.
Fuel gauge reads in gallons. LED indicator and momentary switch to transfer fuel. Works great.
BLT Offroad Avalanche