Some early 3000s and all 3400s had the cowel, hood and nose mounted about 1 3/4" higher than the later ones.
This required a different cowel, hood brackets and a taller fill neck on the tank.
Look at the difference in the height of the dash vs the steering wheel and throttle handle in the two photos below.
I think I have a good gas tank from a high tin 3000 here. Have to look around.