My 70 Dart ,ride height wont stay set

All new parts ,saw a post from years ago on here .
Person had same problem said it was fixed but never really said what fixed it
Torque all bolts,anchor cross member is go .Set it up go 20 years falls all the way down 6 cyl car now 340
Try explaining a little more and give a better description of the parts you're using so members don't have to ask a brazillion questions. That last sentence is pretty cryptic.