1973 duster front suspension upgrade

You want positive caster so the car does not wander at higher speeds. With not enough the car kinda has a floating feeling. If you put in too much Positive caster with a manual steering box, it will have very high effort to turn the steering at low speeds. When you set the camber to negative to improve handling, the positve caster will not adjust enough. The offset bushing helps you get back the Positve caster and have enough negative camber at the same time.
Check these out: http://www.stockcarproducts.com/align11a.htm
http://www.stockcarproducts.com/align11.htm
http://www.stockcarproducts.com/tech1n.htm