Just a slight correction/addition.
We did get the emission control's on the 78 model. Mine was bogged down with airpump, air injection and of course those wonderful SU's that Niassan had left over.
I'm of the opinion that the last model year of the 260Z in OZ was made up of any gear that couldn't be used in a 280ZX, needless to say that included all the accessories that came on the 260 block.
Thankfully, they must have used all the bumpers, otherwise I guess they would have been value added to our domestic import.

Roderz, welcome to Melbourne, unfortunate with the weather the past few days, hopefully it will clear up by the GP...