My engine code is YU and if I did my homework right it is a 2bbl 350 out of a 1970 tempest. I watch a video where a guy took his tank out, put a log chain and solvent inside and shook it around. Looked like a lit of crap came out. Byt who know how much was still in there. Didn't seem like the best idea. Hey on your floorboard, are you doing a full replacement or just patching it up? My drivers side floorboard has a good size hole in it I need to do something about. If I could weld worth a crap I would probably just patch it. I did see many years ago at a Starbucks rod and custom shoe instead of carpeting the interior, he rhino lined the bottom. Actually looked really good. Had to be early 90's or so. I'll probably have more questions for you as I move forward. If you don't mind anyway