OK Larry, sunny day so I could drag it out, here's the beast:
from outer side, and
from back end [measurements are outside the flange, which protrudes about 3/8-1/2"] .... really doubt you can make a universal tank work unless it's smaller and you do some creative mounting - notice the major indentations in the tank and in the bottom flange, these are needed to fit in the original spot and take the mounting straps, and then there's the area indented at an angle where the fill tube mounts, the shape was designed to snugly fill the space available .... much more "messing around" than having your old tank dipped and coated [and straightened if necessary - the pictured one is dented under the front and the drain fitting is ripped away]
Bill