I was in your situation, generally, with my '53 a couple of years back. There are occasionally pans available, but they don't generally cover enough area for a really bad situation. I made what amounted to new floors (salvaged the center hump for the most part, which saved a lot of shaping) out of 18 gauge steel, which was used on '53's and as far as I know was used on all Kaisers and Frazers (floor support channels seemed to be 16.) Had I used the patch type panels I would have had to add a lot around the edges anyway, so they didn't seem to have much of an advantage. I believe the early series' have flatter floors, so should be less of a project.