Rear end swap/install

Id like to suggest just buy new u bolts and nuts. Cut the old u bolts with a cut off wheel and be done with it. Don't bother trying to save any of that stuff as it's likely at least 1 will not be reusable. Don't cut the u bolt at the top because you may not be able to rotate the bolt out of your way. Cut at the shock plate.
Where is the best place to buy the correct u bolt kit for our cars? (1968 Dart 270)