The previous owner of my Blazer did this and I like it. The main difference that I can see is the metal straps that hold the tank in place. If I'm not mistaken the original tank straps ran side to side under the tank. The newer 73+ style runs front to back, at least thats how the PO did it on mine. He just drilled some holes to one cross member and added another out of square stock. I am in the middle of rebuilding my blazer and I plan to freshen up this tank and re-use it, as far as I can tell it is the 31 gallon variety.