Marty, I don't know if the hole for the ordinary Sierra 3 dr's wiring is different from a 3 door Cosworth but it is certainly different from a Sapphire which has two holes.

Paul - my XR4i is a 1985 shell (proved by the later B-pillar door catches) but it only has a narrow tunnel and single bulkhead hole for the near-side wiring, and the shape of the bulkhead at the fusebox is very different from the Mk 2.

Typical Ford - keep mixing and matching. Even the looms changed in 1990.