Ok so my buddy just bought a 69 coronet and was wondering how much of the power disc stuff he can use off his 81 mirada since it has all new parts on it .Or should he just get a conversion kit from wilwood or whoever.He really want's power brakes but isn't wanting to spend a ton on them .Any idea's?

I think an '81 Mirada is a bent bar car so most of the stuff will transfer. He'll need custom brake hoses since I think the '81 will have rear hung calipers with the hose inlets at the bottom.

do we need to use the upper control arms like you do on an a body or will they be the same ?

Use the UCAs from the Coronet. He will probably want to buy the Moog problem solver upper ball joints to aid in alignment. Do the calipers hang to the front or rear on the Mirada? If there is a sway bar on the Coronet you will need to hang them to the rear. All you have to do is switch the spindles from side to side if there is a sway bar issue. I understand the 71 Satellite brake hoses are the way to go for that swap. I'm not 100% sure on that but I'm sure someone will chime in.