I have a '51 Chevy 3100 Carryall. I too, am replacing the floor. It's a big project but, so far I've removed the perimeter carriage bolts and will continue remove bolts on the cross member support irons. I recently replaced the wooden "body support blocks" so I am familiar with raising the body up, but to install an entire floor is a "ramped up" version of this !! LOL! My plans are to replace the existing floor with reclaimed Oak planks, from a semi trailer floor. They are 1" thick x 1 foot wide, plus channeled on the edge. I'll replace the current support iron underneath with new angle iron and carriage bolts. I'll have the planks cleaned up at a local wood mill and apply epoxy sealer on the bottom to help water proof it. The top side will be stained and varnished. I know this not what a lot you guys would do, but I always say as I look at someone else's truck and Think..."now why in the heck would they do that!!? I back up and reconsider my opinion & I say to myself...first off it's not mine and they didn't ask for my input and I didn't pay for the work done it plus and most importantly that truck is not mine! BTW I am amazed at the amount of knowledge and wisdom I read within this forum, I take advantage of it because I consider myself a rooky builder, this is the first one I have "gone through." The others all I wanted was to get them on the road, this one means more to me and I want to rebuild it the best I can with the resources & the skill sets I have (& those skills to come) that also means including this forum as a most respected source of information.