Well after I get moved to our new residence next week and everything organized I plan on building a set for my 1st gen and for my 75 dodge too. I KNOW my truck need some ladder bars. Last summer I had my truck hooked to the trailer two trucks on it and the trailer hung up. Locked it in low 4x and eased out on the clutch. I was watching the rear tire because if i spun the tire the truck would wheel hop. I was witnessing the tire moving about 6inches forward without the truck moving at all:--) Also when accelerating on rough roads I can feel the suspension loading and unloading. Look at the front of you rear leaf packs. Mine have rust comming out from in between the leafs, indicating to me that the springs are moving a bunch. I have my truck tweaked pretty good(lots more than stock) and I don't baby it. So mine might be worse than others. Mine is a 4X with stock rear 6inch blocks that don't help either. As far a companies that make any I don't know of any, and I will build mine the way I want them for little to nothing. The ones I am going to build will be mounted on the front of the axel tube below the center line of the tube but not underneith. I am pretty sure this will work the way I want it to without sacraficing groung clearance. I might use the top link of a tractor three point hitch. Cut it in half and weld in the correct length of pipe. These already have nice strong eyelets on them, and are threaded so that with a quick twist the length can be adjusted. One end is RH threads and the other is LH. I will probaby not make it a four link or three, just the two bars.
Michael