67-70 Dart gas tank filler neck W/vent

SGBARRACUDA said
Measuring along the top of it the round tub end to end is 26 3/4”.

Thanks I see that it is shorter than a 1972 but I wonder if that’s how they get the 18 gallon vs the 16 gallon tank since the 72 and up have vents. I was thinking of switching to the older style so I won’t need a return line.