I braced my 69 vert with angle iron (actually old bed frames) from the top fender mount hole to the top of the rear jamb. I welded a metal plate and drilled a hole and used the fender mount bolt for the front and then mig welded the rear section to the inside of the jamb. I then welded another piece of angle iron from the drivers side to passenger side butted against the rear jambs and welded to the door brace angle iron. I had the car on a rotisserie for almost a year; took out the complete floor and trunk floor, put in all new floors, braces,inner rockers, re-welded the rear seat back plate thingy back in and took it off the rotiseerie. The doors still fit in perfect. No sagging.