It's very important to have a "foot" that you can lower to the ground while using the crane,so the weight gets put on that instead of the trcks springs and frame rail-I neglected to use mine too many times when I was in a rush,and more than once I lifted the drivers side front tire off the ground when I lifted a heavy load with the crane (mounted on the right rearmost corner of the truck).when my truck finally rotted away and blew the TH350 tranny (lost reverse!),I decided to part it out,and when I removed the flat bed,the frane rail on the crane side was a good 2" lower than the other one!. I have a flatbed like yours I kept off my last 4x4 plow truck that also had a crane setup like these,only home built out of a railroad traffic gate lift.I really tweaked the frame on that truck,I used it to haul scrap and lawn tractors,engines,and did deliveries with it,when guys wanted an engine or tranny from the junkyard but lacked a truck to haul it with. I picked up a crane very similar to that one at a flea market for 20 bucks a few months ago-it's hand winch had a stripped gear and the bottle jack's pump piston had pulled the pivot pin out,I fixed the jack,but haven't fooled with the winch yet-I have electric ones I could adapt or a worm gear hand cranked one I could swap on it.I've been wanting to put it on my '82 K2500 ,but it's stepside bed has little room and I'd prefer to mount it on the outside of the bed between the right rear fender and 'll take some engineering to make a sturdy enough bracket to do it however,and my trucks frame aint in pristine shape,so if I do put it on it I'll have to be carefull not to pick up really heavy objects.