They shouldn't be too far different. Different is OK, but if it's drastic then it's a sign of a failing torsion bar or a weak or imbalanced leaf springs.

How much difference is acceptable is anyone's guess. I would suspect no more than a few turns. The adjustments on my 69 383 RR is almost identical.

Do the tires match side to side, same inflation side to side, no damaged or worn bushings, and cross caster within .5 degree? Take a real good look at the rear leaf springs as well.