Just ordered the front/rear panels from
classicfabrication.com your on-line source for floorpans for your classic car havent gotten them yet. They dont make the inner rocker piece any more but thats not a big deal. I Should be getting the car up onto a lift next weekend, so I will let you know how stiffening goes. My plan was to tie in 3x3 tubing from the body mounts in the rear and the rear frame rails, outward and then forward to where the front support rails are. I can get another picture from the owners manual to show where all the main supports are.
Plenty of work to do on the floor for me but it was cheap and its a good way to learn before I hack into the 40' Ford Pickup.
Dalton