Some people will put Super Stock springs in an A-body with both sides being the same part number. Those are around 160 lb/in. Then they have the springs de-arched. Richard Eherenburg did this in his Green Brick car.
You have to use the same part number both side. S/S spring load one side of the car more than the other to react to engine torque and other drag suspension stuff. So the car will not sit level in the rear. I just helped put a set of those S/S springs in a clone Hemi Dart today. Car is all caddy-wampus in the rear like they were originally.
