In that case I would think that either the body bushings are shot (or the holes/nuts they mount to, or the holes in the subframe may have rusted into slots) or the subframe may be pushed back or twisted on one side. Visual inspection with the car on a lift, combined with measuring simple things like distance from firewall to core support on each side, will help isolate the problem.
Vikki 1969 Goldenrod Yellow / black 400 convertible numbers matching