Front end geometry

Not being able to adjust enough positive caster in our A-bodies is a normal situation with stock parts and it does make it steer kinda funny but nothing like what your describing.

Back when I rebuilt the front end on mine and took it to be aligned the guy knew them real well and did the best he could but the best caster was -1.7 degrees. That's about 3 degrees less that what it should be. It drives real straight and doesn't wear the tires and the only thing it does not do right is it doesn't return to center when turning corners.

To make sure they can adjust in enough caster you need to either install offset UCA bushings to force more caster or install tubular control arms that have adjustable rod ends to get the extra caster you need.