8.50 to 7.50 unibody with stock floor/firewall goes from a simple sportsman cert to the SFI 25.5D for 3600# max. Funny car cage, additional tubing in the floor and some things installed differently. Depending on how they were built, I've seen 8.50 cars that needed to be torn apart and redone to get them right for the 25.5. Wasn't as simple as adding bars. On a car going into the 8s, I would go on and make it legal for 25.5.