The locknuts on the j bolts were tight for me too, not sure if it twisted them, but it sure did take some work to put those on. Make sure you didn't tighten the j bolts to the point where it notched the frame, not sure what you could do if that did happen.
Same thing on the end links. I actually used the bottle jack to hold everything together/compressed so I could start the nylon lined nuts. (not enough to lift the truck though
)There was about 1 to 3 threads showing after the end link nut when I was done.