have you seen the thickness of the 51? crap they build tanks out of lighter gauge than that thing is made of. I had to repair my dads 51 chevy truck when some crazy lady hit him, totaled a 70 chevelle but just crumpled the front fender and didn't hurt the spring steel bumper. It too me a torch, 290 studs and a lot of cussin to bring that fender back out to shape. Steel was ".090 on the floor and 080 in the fenders since it was stretched a bit from stamping operations and a ***** to move. Every rubber floored vehicle I have owned has rust on the floor. new old or in between. might as well rip it out and just paint it for better protection.
