[mr48chev]

First you have to find out exactly what caster you have now. Then figure out what change if any you need to make. That usually takes a trip to a front end shop unless you have access to a caster/camber gauge.

There is probably an old school shop in San Angelo that has a stick on the hub gauge to check it with that doesn't charge a fortune like the fancy places with the wizz bang 4 wheel alignment electronic machines. Or if you have some buddies with circle track cars a lot of circle trackers have their own caster camber gauges in their tool boxes.

Someone will no doubt come on and tell how to do it with rocks, sticks and string or something but those home brewed systems don't always work the way you want them too nor are they anywhere near accurate.

Take a look between the springs and axle to see if there are already shims in there as they were quite often shimmed to get the trucks to track better on the road years ago. The shims are readily available in a variety of degrees.