Axing the sides of a fuel tank is a traditional look. Caving in the sides looks great and is fairly easy to accomplish. There are two approaches that I am aware of and I have used both. One requires more welding but less body filler and displays a fine edge, the other has more body filler, less welding and displays a radius edge. In this article I will be discussing the first technique becuase I prefer the look and lack of body filler required. Technically you can do this to any tank although I think it looks best with a mustang style tank.
The first thing you have to do is define your cut line. I do this by leveling the tank and using a height gauge to mark.
After marking a cut line you want to take time to actually follow the line and get a clean cut edge. You can use a small friction wheel or air-saw for this.
Once you have cut the sides off, you are going to invert them and swap sides. So the piece from the right is going to be welded to the left and vise-versa.
Take your time lining up the panels before welding. You want to minimize any gaps for a nice clean weld.
After welding you can go through and do a little metal finishing.
Enjoy the work and take prove in what you have done!
Eric
If you know the history behind this look please leave a comment.