When the Bugeyes raced at Sebring, they took two bugeye tanks and cut the tops off inside the flanges, flipped one on top of the other, and welded the two tanks together at the flanges, effectively doubling the capacity. They had to cut a hole in the boot floor for the second half of the tank to stick through, but no big deal, as the saying goes, "because racecar". They must have also welded in the fuel filler tube to the second tank because they filled it through the normal Bugeye hole in the boot with a flip-top filler lid.