ADELAIDE, Australia – The Great Ocean Road is arguably one of the world’s most beautiful drive routes, stretching for hundreds of miles west of Melbourne.

Here, the term “scenic overlook” is no tourist trap. Plummeting cliffs, crystal blue sea, pristine beaches and rocky outcrops known as The Twelve Apostles – all under blazing sunshine much of the year – await those willing to pull off the road. Think Pacific Coast Highway, multiplied by 5.

In some vehicles, however, drivers are less inclined to stop.

GM Holden Ltd.’s all-new V-8 Commodores, for instance, begged for a flogging during the 500-mile (800-km) jaunt from Melbourne to Adelaide, hosted by Germany’s ZF Group. ZF produces axles and steering systems for the all-new vehicles, which began production here last year.

But with every throttle tweak, our Australian guide reminded that highway speed limits are 100 km/h (62 mph) and anyone caught going faster than 130 km/h (80 mph) would lose his license, no questions asked.

Come on, mates! Where’s that Australian zest for life? Tourists can climb to the top of Sydney Harbour Bridge but can’t drive faster than a bounding kangaroo? Didn’t Australian cinema give us Mad Max?

No worries. Having nothing to lose (and no Australian driver’s license), I took my chances when prudent – and loved every minute of it.

Much was at stake last summer when Holden launched the new Commodore large cars, a program estimated to cost $1 billion.

Holden needed a domestic hit. Halfway around the world, at General Motors Corp. headquarters in Detroit, an anxious parent was hovering, too, with plans of its own to bring legitimate muscle-car contenders to U.S. streets by leveraging Australian rear-drive expertise from the global Zeta rear-wheel-drive architecture.

GM honchos in Detroit can rest assured: The new Commodores are powerful, stylish, comfortable and generally pleasurable to drive.

When the Adelaide-assembled Pontiac G8 arrives in U.S. showrooms at the beginning of 2008, it should be well received, assuming the G8 reflects the same quality as the other Commodores currently on the road here.

We drove the Berlina Calais V-Series and the Omega SS V-Series (both with a wheelbase of 115 ins. [2,915 mm]) and the long-wheelbase (118 ins. [3,009 mm]) Caprice, whose spacious backseat is befitting a limousine.

Appreciating the vehicles was easier than getting comfortable holding a steering wheel on the right side and manually shifting with the left hand, as we did in the SS V-Series.

The other two vehicles were equipped with smooth and precise-shifting 6-speed automatics, although 4- and 5-speed autos also are available in the Commodore range.

The SS V-Series, by the way, is the closest approximation to the forthcoming G8. With its ground effects, spoiler, blazing “chromatic red orange” paint, muscular stance and plenty of body-color trim inside, the car oozes Pontiac “excitement.”

Styling is decisive, edgy and easy on the eye, with a high beltline and European flair. No identity crisis here. It’s a dead ringer for what should be the next-generation Impala, assuming GM intends to give it more attitude.

In fact, industry speculation has the next-generation Impala (currently front-wheel-drive) going RWD, borrowing from the Zeta underpinnings.

The new Commodore bears none of the squat, roundish proportions of the previous-generation Monaro, which was repackaged for delivery to the U.S. as the Pontiac GTO from 2004 to 2006.

Although a solid performer, the GTO disappointed muscle-car purists who complained the Monaro looked nothing like the GTO of the 1970s.

GM need not worry about armchair cynics who question the wisdom of sourcing yet another car all the way from Australia.

The G8 should be much better than the 2-door GTO, and it will have 4-door practicality, too. GM desperately needs a solid sport sedan in its portfolio. Who cares if it comes from Down Under?

All three vehicles driven had the same Generation-4 6.0L V-8 (produced in Silao, Mexico), each churning out 362 hp at 5,700 rpm and 530 Nm (391 lb.-ft.) of torque at 4,400 rpm. The engine is a 90-degree all-aluminum OHV V-8 (codename L76) with cross-flow cylinder heads.

These mills were eager to perform and delivered a guttural dual exhaust note when pushed hard. But – sorry, Holden – the Ford Mustang’s V-8 still tops the charts with its tailpipe symphony.

The three Commodores definitely played a more restrained exhaust tune, but that’s OK. The Commodore lineup encompasses daily drivers and family sedans – not just muscle cars.

The Commodores are surprisingly versatile. A multi-link independent rear suspension, combined with variable ratio rack-and-pinion steering, provide great maneuverability, especially for a car that tips the scales at 3,979 lbs. (1,805 kg).

We didn’t get to drive the 3.6L DOHC V-6 also available in the Commodore range. In Australian spec, three versions of the V-6 produce between 234 hp and 261 hp and between 239 lb.-ft. (325 Nm) and 250 lb.-ft. (340 Nm) of torque. The highest output V-6 (code name LY7) will come to the U.S. in the G8, as well as the V-8.

The V-8, derived from the 6L engine used across GM’s fullsize pickup and SUV lineup, never once felt overwhelmed by Australia’s undulating pavement.

But those hills also gave us the only car trouble we had during our 2-day drive.

On the long descent on the road heading north into Adelaide, the automatic gearboxes in both the Caprice and Berlina Calais – amazingly at the same time – downshifted into third gear and stayed there even when the pavement evened out.

Shifting into auto-stick mode did no good. Eventually, shifting into neutral, then back to “drive” did the trick. A Holden engineer tells Ward’s the downshifting is intentional, as a method to use engine braking on hills.

No word on whether that feature will be on the U.S.-bound G8. The V-6 in the G8 will be paired with a 5-speed automatic, while the V-8-powered G8 GT arrives with a 6-speed automatic. Pontiac promises the 6-speed manual, lifted from the new Corvette, will be available in early 2008.

Performance comes at a price in the Commodores. In Australia, the High Output V-6 is rated at 21 mpg (11.3 L/100 km), while the V-8 achieves 16 mpg (14.4 L/100 km), which can be tough to swallow for Aussies paying the equivalent of $5 per gallon for petrol.

Environmental Protection Agency fuel economy ratings for the U.S.-bound G8 have not yet been released.

Also to be announced is pricing.

In Australia, where cars tend to be more expensive in general, pricing for the base Commodore Omega begins at $27,895 (A$34,490), excluding dealer and government charges. The top-of-the-line Statesman and Caprice approach $56,600 (A$70,000).

Still, Holden proudly proclaims many of the all-new Commodores are less expensive than the previous-generation models they replace and are better equipped, with electronic stability control as standard.

Interiors on all three vehicles tested reflect clean fit and finish, quality materials, handsome design and thoughtful ergonomics. Seats are comfortable and supportive, without feeling too soft.

Pontiac says the new G8 will have more interior space than the cavernous old Bonneville, which ended production in 2005, yet will be shorter overall than the Grand Prix, soon to be replaced by the G8.

Adelaide production of the G8 begins in October, and saleable units should arrive in U.S. showrooms in January or February.

Next up after the G8 launches will be the Zeta-derived Chevrolet Camaro, to be built in Oshawa, ON, Canada, beginning next year.

And perhaps further down the road, AutoWeek reports GM Holden is working on a V-12 that mashes together two 3.6L V-6s and could find its way into a future Cadillac model. Testing is being done in Zeta-based prototypes in Australia, the magazine reports.

Surely the V-12 mule wants a flogging – perhaps on the Great Ocean Road.

tmurphy@wardsauto.com