I can't even remember when I started going Sean, my father used to take me, but he didn't much care for speedway, so it wasn't as often as I would have liked. But the saloons were my favourites, and all the cars then were built from original road cars, then heavily modified. I was born in '71, so I guess it must have been early 1980s when I first started going. But I think you are right, there were at least two Monaros racing then. After a few years the space-frame cars began appearing. These were mostly Monzas and Toranas.
Here is the Wemyss Tiger. Note its right hand drive.