16. The tunnel begins with the driveshaft portion; first a piece of tapered 18-gauge sheetmetal is cut. Beads were then rolled into the sides of the tunnel, and a 45-degree angle was bent into each edge. Next, a long piece of rectangular tubing is clamped to each break and the tunnel is bent over a welding bottle. The tunnel is then placed atop the two floor halves, where the previous 90-degree breaks in the floorpans and the 45-degree break in the tunnel are adjoined.