Hi Dave,
the Corolla diff is from KE30-KE55 - they all look the same to me! But the one we use is an Aussie made BorgWarner diff fitted because of our local content/assemble laws in the 70's, so they probably won't be the same diff in the NZ Corollas.

In Aus they had 3.9, 4.1, and 4.3 ratios. They are about 3" wider housing - almost perfectly matches track after Stanza or similar strut swaps. Spring mounts line up OK on the 1200 springs. I won't go into too much detail because they're probably not available over there unfortunately.

Harry