Once i removed the body off the frame and set it up on 4×4 wood posts. i noticed a lot of flex in the body. I then measured the gap between the doors on each side and noticed about an inch difference. Big problem! after adding some supports under the floor to get everything back into alignment. i welded two steel support bars from the top of the windshield frame to the back of the truck area. That defined stiffened it up and the body was now ready to go on the rotisserie. i have seen people add the supports between the doors opening. but it seemed that the car was more accessible without anything blocking the door opening. one thing i would have done different is install the braces BEFORE taking the body off the frame.
used a 2 ton hoist attached to an I beam in the ceiling to pull the engine and body off the frame.