6pak, those numbers are for the factory XHD springs, or Hemi springs as they are commonly called. The 984 goes on the right, 985 on the left. The are a biased design to control torque reaction during launch.
Banana, see the above posts for determining if you have stock, XHD, or SS springs. After 30 years, it could be any or none of the above that have given you your current ride height.