I have been told that Ford Cortina calipers will fit inside the standard 13in mags and are simple to fit. Now, there arent that may Cortinas around (even here). Does anyone know if the Mk3 escort or Mazda 3 calipers are the same ?
I think I am right in saying that the cortina calipers are the same caliper as the capri ones but with without the spacer to make them wider as the tina disks are not vented. They are the same calipers as much of the ford range and were also used on some of the GT6's. I think however, as the 7's disks are small and not vented any braking advantage gained will quickly be lost through brake fade due to over heating. To fit the vented capri disk you need a modified hub. But you are right however they should just fit inside a 13inch wheel.
If it doesn't fit you obviously need a bigger hammer.