I recently acquired a gutted 1957
Flying Cloud that I thought had a solid floor in it, turns out the PO just screwed 3/4 ply to the old rotten floor.
In searching the forums I found a wealth of awesome information on this topic and have gotten started on fabricating my "forever floor".
My AS had a 5/8 ply floor so I went and picked up 80ft of 5/8 x 5/8 x 16GA(.0625) tube steel to get started. The 5/8 square tubing weighs .5 lbs/ft so I anticipate it will be nice and light. Also the material is only 11.50/20ft so thats a plus.
I am leaving the body and belly skin on.
Use the old subfloor as a bending template and double up pieces of 5/8 square around the border of the frame to create a 1 1/4 x 5/8 rectangle for the body C channel to rest on. bracing is tbd.
Still need to figure out-
1. is this a good idea?
2. weld in place OR on bench then install
3. insulating gasket to prevent galvanic corrosion
4. subfloor decking over frame
what do y'all think? Here are some photos of the front section-