In a previous post I cut a huge hole in the top of the monocoque / foot box to fit the Restmod Air evaporator. Although I have the optional removable side impact bars which add a lot of rigidity (they have welded steel plates that pick up the upper control arm mounts and the upper shock mount) I wanted to ensure that I wouldn’t have a structural problem.
The first step was to fill in part of the circular access hole with 1/4” plate. As can be seen in the photo below the edges were chamfered to get good penetration and a flat weld. Once that piece was welded, a 3/4” x 1-1/2” x 1/8” tube was welded to the top of the monocoque. The right corner is now rock solid.
