Yes I have done a few , not sure why this is in the Fuel section !
The 74 is the hardest to convert , you need a set of the front mounts & may need to make new holes to line up with the frame mounting points as the facxtory used 3 bolts each side , 72 used only 2 . The rear is tougher to do there is a large beam back there , again you may be better off with 72 mounts but the holes in the bumper may not line up , also the mounting points on the frame may be different but I believe they do line up . You can just cut the beam up & modify that to move the bumper in which is what I did , I just cut two 8" sections out of the beam to use for mounting . I did mine back in 81 . I removed close to 60 lbs doing that . You will want the 70 fill panel at the rear to fill the gap between the bumper & body at the top . I recall we used 72 mounts on the rear on the Chall I converted in 2006 .