Article from below link,
This gas tank is the same as the 1/2 ton “Single Unit” body trucks (Suburban, panel, and canopy express) during all the Advance Design years, 1947 through early 1955. With the 3/4 ton the truck has a longer frame so its gas tank could be longer and thus thinner yet it held the same fuel volume. it is important to realize this less depth allowed the tank to be higher above the ground. Therefore, it eliminated most tank contact with “high center” road rocks on dirt roads as with the 1/2 tons. To date, the 3/4 ton gas tanks are not being reproduced!
Dimensions are: length 24", width 12 1/2", and depth 13".
Source
Underbed Gas Tank I do not think its a 47- early 55 1/2 ton Suburban, panel, and canopy express gas tank.
