The Stovebolt Site Forums The Shop Area Driveline Steering opinion?

I'm not saying 6 degrees is wrong I just wanted to know the reason behind so much and didn't want to end up adding to large of a shim. My thinking is if the factory spec is 2 degrees and I add a 6 degree shim that makes it 8 degrees total one way and shim flipped 4 degrees the other way. Since I'm pretty sure these trucks have some caster from the factory I just wanted to be sure before I order my shims.