Hi guys would the sierra calipers and discs goes with the cortina mk3 uprights ? thanks Alex

No

However most other RWD Ford brakes fit ie MK2 Escort, Mk2/3 Capri, & 70s Granada

thank mate,i forgot to mention for the front not rear,if it is the same thats good cheers

As do PSA calipers if you use the right disc

CAn get you a nice set of Wilwood Brakes