Hi, if you take that rib off and lay it flat on a 2x4 and use a rubber faced mallet and another piece of 2x4 you can straighten it as it is made out of aluminum. I've done quite a few of them. If the rib is wavy from top to bottom you can use a screw driver in the rib cut outs or vents wrapped in a good rag and twist the screw driver hence straightening the wave. Good luck, Tim