Here's where I had to do a little math. The wishbone mounting points had been 4 1/2 inches below the chassis 'rails and I wanted the 'bones to remain parallel with the 'rails, and mount through them. With the 'rails 4 inches high, and wanting the mounts at their midpoint, I added 2 inches (half the height of the 'rails) to the 4 1/2-inch measurement, meaning the kickup had to be 6 1/2 inches high. Using a set square I transposed this vertical measurement to the box section and marked it accordingly. I now knew how long to cut the kickup sections, which worked out very close to 7 inches.