Small correction...it was originally built as a "Group One" car. Trevor bought in a heap of bits for the car from UK Chrysler Competition Centre through Todd Motors including the Brazilian wheels suspension etc.
I think the engine is now in Hamilton, it was on trademe several years ago and I spoke to the seller who said it came from Chch which makes me think it was Crowes. I think the diff is in my car? as my car came from Dunedin and the diff casing is the Heavy Duty type with thick tubes and Huck Bolts. To my knowledge only 2 HD diffs came to NZ, one was the spare for 76 Heatway that didn't go back and the second was for Crowes 1800 car.