I had been told as a boy that this would work. I got holt of a tank from Cycle Recycle Part Deux for about $25. But its not a slip on fit. At first glance doesn't look bad to my eyes:(color match is pure coincidence)
From the top one can see the reach of the mounting tab is perfect.
But from the back, you can see the equalizer tubes had to be bent straight down (they were at 90 degree) then the last 4 inches of the tank hit the frame tubes.
My machinist is "Saldana Racing Tanks (We do more than tanks)" so if I decide to go with this, I'm sure they can make it fit.