There should have been shims on both sides to correct the caster, and even then there should only have been one per side. It almost seems like someone has tried to compensate for either worn bushings or a twisted axle. I would put it back together without the shims, then get it shesked at an alignment shop. You may have to find one thet handles large trucks, most smaller shops only do modern vehicles and may not have the knowlege or equipment to handle a strait axle. They will be able to tell you if the axle is ok. You may consider having some caster put in, that will give more stability to the steering when travelling on the highway. I'm thinking of doing that to my '55, if I can find the right width shims.
