Benefit of eccentric control arm bushings?

[intergalactica]

Exactly what are the benefits of eccentric upper control arm bushings? How would I know if I need them? My car is a '67 cuda if it matters.

 

[abodyjoe]

some install them to gain more caster for handeling. some cars are bent and need them to get the alignment to stock specs..

 

[caferacerx]

they increase the range of adjustment for the upper control arm, the factory alignment specks were designed for bias ply tires not radials, so on some car's they help achieve an alignment setting preferred for modern radial tires