The original tank came from Total Performance, made of steel, advertised to be used with T-buckets. It is rectangle.
The second tank is from Dan's (a Dune Buggy outfit), made of heavy duty Poly, and is cylindrical (10 inch by 33 inch).
Neither tank has a vent tube, so both tanks would have to be drilled and a tube run. Frankly, I don't want to do that unless it's absolutely necessary.
Because of the size and shape of the tanks, I can match the bottom or I can match the top, but I can't do both. Which is better for faster filling and/or for total fuel capacity?
Another option mentioned by a friend would be to run a fuel switch between the two. Run one tank then the other so I would not have to worry about the height of the tanks. Advantages/disadvantages of that option?