Since the frame rails were dented up pretty good from wrong floor jack positioning, I decided to replace them and this would also give me the opportunity to really get the original metal floors flat, and the metal shrunk and tight. They were surprisingly clean inside.
This is the floor pan after removing the spot welds and frame rails.
After some wire wheel work, and metal prep acid wash with Scotch-Brite, I worked and shrunk the metal with a shrinking rod and them smoothed it with a shrinking disk. Nice and flat getting it to what original would have looked like, leaving all spot welds and original deformations in place. I then lightly blasted the overlap areas and applied Weld-Thru paint.
I then fitted the new frame rails, they took a bunch of work to get the correct shape and to match the original contour of the floor pans. I then copied all the original spot weld locations and drilled 3/16 hole to plug weld. I used several Cleco clamps to hold it in place and tight up against the floor pans.
Next I used my MIG and plug welded them in place
Finally I will grind smooth the plug welds
More after the weekend