I have not dealt with anything but 1965 3/4 tons. However, I bought some LMC trailing arms years ago. I'd planned on replacing the arms, and had some u-bolts made up to match the existing ones. I was going to take it to a local shop to have them do the work so I didn't have to deal with the old bolts holding them to the frame. Glad I checked everything first. The 3/4 ton arms seem to have a wider bolt pattern, so to speak, for the u-bolts. The u-bolts would not go through the C10 arms from LMC. So they sit unused. And LMC doesn't have C20 arms available the last time I checked.
