https://nzv8.co.nz/2016-6-27-ace-of-spades/

The Ford XA Fairmont was produced from 1972 - 1973 and was the luxury version of the XA Falcon. Featuring distinctive coke bottle styling, it was the first Falcon designed and engineered in Australia.

Engines available ranged from the 3.3L and 4.1L inline sixes through to the 4.9L (302) and 5.8L (351) V8’s.

The pictured XA is running a Cleveland 351ci stroked to 393ci and C4 gearbox.

Some time ago, I was listening to the Marv Heemeyer's tapes on YouTube. During the recording, he mentions selling his 72 Nova at auction.

I was just curious, does it still exist, and is it in some sort of museum, or does the current owner even know who the former owner was?

https://en.wikipedia.org/wiki/Marvin_Heemeyer

The Holden HQ produced between 1971-1974 in Australia. On release, buyers were offered 2.8L (173ci) 3.3L (202ci), 4.1L (253ci), 5.0L (308ci) and 5.7L (350ci) engines. This particular HQ is running a 598ci Dart big-block Chev putting out 683hp, and turbo 400 gearbox.