Back when I raced my Challenger on the weekends my roll bar had 6 inch plates that were bolted to the floor both on the Side bar, main loop and back bars, with plates on both sides. The Cuda we are building the plates are welded to the floor close to the side and are not flat but follow the angle of the floor to get the Loop wide in the car to make side bars easier to locate with Door Panels. The 6 inch plates do not have to be flat but must be at least 6 inches. When we started to look at the today rules it was hard finding information on roll bars. When the Chassis Cert guy came over to do a 850 tag on another Car a 1965, we questioned him a ton of what is legal. There are kits for sale that are pretty good almost bolt ins but the Cuda we are building the Chassis is super stiff with us building the Roll Bar and frame connectors the way we did. Only the first few passes will tell us how well we did but when you have a Template sitting next to the Cuda it makes it easier to copy a lot of things.