Ball Joint Question

I want to change my 85 caprice from the small bolt pattern to the large bolt pattern. I know I need the rotors and calipers, as well as the spindles. My question is, are the a - arms the same as well as the ball joints between the small and large bolt patterns?

Most are. If you make sure you get pre-95 spindles you will be fine with your original a-arms. Sometime during 95 they changed to a larger ball joint on the b-bodies.