Chrysler Australia for the years 1958 and 1959 assembled 4-door Dodge Custom Royals and Plymouth Belvederes with their huge fins...
Though these were priced as a 'luxury car' (and sized that way too alongside the '50% of the market' Holdens) they have very few luxury features and there were certainly no power-train options. All were automatic, all were V8s (361 in the Dodge, probably the same in the Plymouth), they were built up from packages from Canada. Also packaged from Canada were De Sotos assembled in like fashion by Buckle Motors in Sydney. Ford were assembling the Fairlane 'tank' models in those years.
We had no Buicks, Oldsmobiles or Cadillacs except a few privately imported ones, but Chevrolet and Pontiac were assembled locally with 6-cylinder engines.
In 1960 Chrysler Australia cut back and only assembled the Dodge Phoenix, now using the 318 Poly engine and Torqueflite.
The local Chrysler offering was the Chrysler Royal which was up against Ford's main big-car seller, the Royal being based on a 1954 Plymouth chassis and running gear and offered with the 250ci flathead six in automatic or overdrive manual form, the 230 flathead six with straight 3-speed manual, while the option of a 303ci Poly V8 with Powerflite (2-speed automatic) was available. They body on this car was pure 1954 from A-pillar to C-pillar, though the roofline was raised a little in 1960, and it had 'Forward Look' fins and frontal styling which increased the overhang at both ends.
Against Holden, Ford offered the Zephyr and Consul range, though the Consul wasn't seen as opposing Holden as it wasn't a six. They weren't to introduce the Falcon until late 1960, while Chrysler didn't bring in the Valiant until 1962.
BMC, on the other hand, had multiple choice. 1959 saw the Austin Westminster - leather seats and a 4-speed or automatic - and the identical car badge-engineered as a Morris Marshal as their 6-cylinder contender. These were like the Humber Snipe, dearer than Holden but not much bigger while the Hawks were an oddball. A little cheaper were the Holden-sized but 4-cylindered Morris Oxford, Austin A60 and Wolseley 15/60 sharing the same Farina-style body and those dreadful Armstrong top wishbones. All 4-speeds (with two low gears) and no automatics.
Smaller 4-cylinder cars were here in abundance in 1959. Simca's Aronde from Chrysler, Hillman Minx (almost as big as the A60s...) sharing bodywork with more expensive Singer Gazelles, BMC's 1500cc B-series engines drove through the B-series gearboxes to frail A-series rear ends in the Morris Major, Austin Lancer and Wolseley 1500, the Lancer being an Aussie restyle. Volkswagen's 36hp Beetle was here in large numbers and the Peugeot 403 sold well on the back of Round Australia Trials successes. Citroen ID and DS models weren't smaller, but their sales were.
Fiat were about to launch their 1800 six, but we had the 1100s right through the fifties as well as Skoda's Octavia. And getting into the smallest car category we had the Renault Dauphine, Fiat 600, Fiat 500, Morris Minor (no Mini until 1960 IIRC), the Anglia and the Prefect.
I hope I haven't missed too many there...