Jason,
I have done this on my '59 Apache. I have caught flak for having done so. I still think it was the right choice, particularly considering the need for weight on the drive wheels. And, no, the weight at the rear cannot come close to causing oversteer, considering the mass at the front.
I used a J.C. Whitney P/N ZX862180N 25 gallon steel tank (Suburban). There are larger ones, but they're vertically deeper. The rest is getting the strapping installed. I use three straps. I found that my mechanical fuel pump will pull fuel all the way from the rear.
Good luck!
