The last TRULY Australian car is gone forever.
Commodore was never really Australian, except the earliest iterations with the proper Holden 4 or 6 cylinder engines, maybe the V8 depending what that was. The rest of it (body, transmission and trim) was a mishmash of European and American platforms over the years. Eventually, Holden's homegrown engines couldn't compete, and were retired in favour of a Nissan inline-6 for a time, then the Buick 3800 and now some GM Modular engines since the 2000s.
Ford, however, started out with the American Inline 6 and tweaked it well enough over the years to radically change it, from a pushrod/flat-tappet 6 to a SOHC, with an Allow X-Flow head. Eventually that designed was retired in the 2000s and replaced with Ford's "Barra" engine, unique to Australia, and an evolution of the older engine.
I know several times Ford imported Ford V8 engines from the USA - whatever flavour was "popular" at the time. The Windsor was one of them.
To the best of my understanding, the Falcon never was based on any foreign platform.
I'd take one over a GM/Vauxhaull FrankenCar ANY day.
Grandfather had a 1993 EB Falcon GLi in
"Everglade Green." Beautiful colour, just a base model. We purchased it from the Toyota dealership it was traded into after he upgraded to a 2005 Camry V6 Altise. Unfortunately, the change from country driving to city driving was not of benefit to the car... Cue numerous head gasket issues and warped brakes, sold in 2009 with 230,000km IIRC.
My reading these days tells me brakes need some aftermarket "thinking outside the box," and heads can be avoided with preventative maintenance on the cooling system and using high-quality copper or steel gaskets when the OEM unit does fail.
Aside from the 4L engine being rather thirsty in the city (Usually 400-450km from about 60L of 91RON unleaded {68L tank}, a comfortable car that was great for the highway!