[dsraven]

this is what the floor from an 88-98 flare side box looks like. the box with the fiberglass step sides. it is pretty well just a rectangular and the edges of it are already bent for attaching the box sides. I don't have a width dimension or a length dimension, sorry. there are a few spot welds to cut through on any of the used bed floors since the cross sills are spot welded on, the front and sides are spot welded on, etc. I use a cheap 1/8" drill bit that I buy at the local princess auto, double ended and sold in a pack of 8 or something, and drill the centre of the spot weld right through. then a 5/16 or 3/8 drill floows that. not too worried about the size of the hole because I will me welding through that hole later so better to have a hole big enough for a good plug weld rather than hope for the best when you can't see if the weld puddle actually contacted the bottom of the weld hole. anyway, you get the idea, like LG says. cheap if you get a used box. if you get one with good outer parts you can likely sell the skins and make your money back, along with the tailgate if it comes with.