Fuel tank for a 20

[JW-Tex]

I have noted that the tanks from this web site appear to be the exact same ones offered at West Marine...just less expensive. I have a 1969 that had a deck tank so I have no old tank to measure...I did try and measure between my stingers and I was at about 23 inches...but it was dark and I do not have good access or angle to get an exact measurement. I may go with the 40 gallon tank instead of the 55 as I will be running a fuel effecient 4 stroke.