fuel capacity on 23' tsunami i/o

[bobfish21]

anyone know what the fuel capacity on my '74 23 ft tsunami i/o is? its the model with the fishbox between the fuel tank area and just fwd of the engine box. I think its 48 gal.,but i never let the guage go lower than 1/4 'caus i dont think it reads right.thanks for the help, just discovered the site and its really cool!