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A V8 sedan shootout is as Aussie as blowies at a barbie. Add supercharging and you stir up one hell of a hornet's nest. So which of these bad boys has the most sting?

Four hundred and eighty kilowatts. Eight hundred and two newton metres. Meet the E2 Supercar, an HSV GTS-based creation of Walkinshaw Performance.

Four hundred and ninety kilowatts. One thousand and seventy-eight newton metres. That'd be the HDT Blue Meanie, a reprised VK SS Group A based on a VE Commodore.

These two blown V8s push the very limits of plausibility for road-going sedans; a truly formidable pair, they are the grand slammers of contemporary Aussie muscle cars.

This, then, is a primordial V8 stoush. And where does one host a battle between the automotive equivalents of an earthquake and an avalanche? Where does one test tin-tops infused with the supercharged torque to shatter reality and flatten mountains? Mountains it is, then…

Wheels rarely tests aftermarket Frankenmobiles, as the credentials of their creators and calibre of the work is often hard to verify. But when companies with the pedigree of Holden Dealer Team and Walkinshaw Performance unleash their talents on Australia's favourite performance sedan, it's special. Crucially, both outfits also back their work with warranties.

The HDT Blue Meanie descended on our meeting point at the Holbrook bakery, NSW from Sydney. The work of a reborn HDT outfit once famous as Peter Brock's road/race team in the 1970s and '80s, the Blue Meanie sports a modern interpretation of the HDT VK SS Group A bodykit, and mimics its Formula Blue paintwork and white dinner-plate alloys. But it's what's underneath that elevates it.

The Blue Meanie starts life as a Holden Commodore SS. Harrop-designed four-piston brakes (335mm discs all round) replace the stock two-piston jobs. From there HDT goes to work on the 6.0-litre, 270kW V8. Tougher forged pistons and conrods, a re-profiled crankshaft and an entirely new valvetrain are installed to better handle the forced induction of an off-the-shelf Harrop supercharger running 7.5psi.

"We have to keep the boost low to get longevity and reliability," says HDT's Darren Gillis. "Not necessarily out of the engine, because we've put tougher components inside, but the components around it."

Keeping the boost 'low' yields 490kW and 1078Nm - near twice the power of an SS, and twice the torque of a GTS. Adequate? Si.

Gillis says the SS's other powertrain components - Tremec T56 transmission, the prop shaft and driveshafts - are up to the 1078Nm task. He and his team should know, having covered plenty of prototype miles, including an entire Targa Tasmania with a 7.0-litre supercharged V8 version. "The proved bulletproof in our testing so we saw no need to change them," he adds.

The Walkinshaw descends on Holbrook from its Clayton, Vic, home - just a stone's throw from that other Walkinshaw company, HSV - with your correspondent at the wheel. It's been a real struggle to refrain from using its supercharged V8 mumbo to nuke three hours of mind-numbing Hume Highway.

Where the Blue Meanie is based on an SS, the Walky starts life as an HSV GTS. That means a 6.2-litre V8 with new-generation Tremec TR6060 transmission and MRC adjustable dampers. From there, Walkinshaw Performance goes to work, inside and out. Our test car wears a multi-hued green that makes photographers weep, and is decorated with generous dollops of carbonfibre; most noticeably the bonnet scoops and trims above the nostrils, plus the side vents, wing mirrors and subtle boot lip.

Inside the front wheels are a set of 365mm ventilated discs with six-piston calipers, matched by 350mm discs and four-piston calipers at the rear. The 20-inch custom alloys, 8.5-inches wide at the front, and 10-inches at the rear are wrapped in Bridgestone Potenzas. HSV and HDT stop at 9-inch wide tyres; WP has gone further in the name of grip, but in doing so introduces a tyre/body clearance problem when the Walky's slightly softer springs compress - in corners, over bumps, or with a bootload.

Where HDT replaces much of the V8's internals, Walkinshaw retains HSV's standard components. "We use a specially-made Harrop supercharger," says Walkinshaw's Alan Hale, who was an HSV engineer for 20 years. "Power per dollar, a supercharger is the best investment you can make."

"We know the limits of this engine and its components, and we reckon there's plenty of performance to be had if you stay within those limits. Everything south of the engine is standard Holden/HSV. Look, if you drove it flat-out all day long you'd break something eventually. But we know what the 6.2-litre engine can take. We know what the gearbox can take. We have the confidence that our cars can take the kind of punishment we expect owners will dish out."

The Walky's rear end is dominated by big quad exhaust pipes. No surprise, given the intake up front could swallow a small child. No surprise, either, that the exhaust note could drown out an AC/DC concert. In the confines of a tunnel the acoustic reverb sounds like a building collapsing, overlaid by the supercharger's mournful soundtrack.

The Walky and the HDT make Holbrook without undue attention from the boys in blue, but everyone else stops for a look. Truckies crawl down the main drag, shop owners leave their tills, tourists stop and stare. It's unnerving how much attention these two brawny V8s draw, even when sitting still. Not even a Lambo on Lygon Street turns this many heads.

Any chance of slipping away quietly is lost the moment we fire them up. The Blue Meanie's exhaust noise cannons down the country street and the car rocks at idle like a yacht in choppy water. Not to be outdone, the Walky spits and splutters to life like a food critic biting into a crook oyster, but settles into a contented grumble.

We treat the locals to a little aural entertainment on the way out of town, hitting the 50km/h speed limit almost instantly. Keeping your license in either of these would be a fair old challenge.

Surprisingly, both cars are well behaved during mundane touring stages. The Walky, for all its pent-up aggression, drives just like a GTS. It's smooth on throttle transition, and rides comfortably on its softer springs. The spring/MRC combination, however, doesn't cope as well with speed humps it pogoes before calming down, and can bottom out, even at a crawl.

The HDT, with Bilstein suspension that drops it 30mm closer to earth than an SS, rides more firmly than the Walky, and its exhaust booms annoyingly below 2000rpm. Gillis says the production exhaust largely fixes the boom and drone of this pre-production example. Throttle response also lacks smoothness, the on-off transition bringing coughs and stumbles.

Tumbarumba, the town referenced by the Hoodoo Gurus' Stomp the Tumbarumba, comes and goes, and the imposing Snowy Mountains rise before us. Then, a sign: 65km winding road. Game on.

This is the real test of these two insanely potent sedans. Can outputs in excess of 480kW and 800Nm be release with relish in the real world? Are these mountains of mumbo mere lead-tipped arrows best confined to the dragstrip? Or do they have the dynamics to deliver on driver's roads?

Even in third gear, stabbing the Walkinshaw's accelerator is how I imagine it would feel to be gang-tackled by the entire Wallabies scrum. The rear end squats and the car thunders forward, snapping my head back into the seat. Hard.

The 802Nm missile shows disdain for the steep climb. Mountain? What mountain? The full-throated bellow emerging from the quad pipes is enormous to begin with, amplified by the cliff-face shadowing the road. It's louder even than the combined whine of the Harrop supercharger up front and the tortured howl of the Bridgestones out back. Even in third the traction control light is flashing as its massive torque challenges tyre grip.

First red-blooded rush done, it's time for a more measured approach; to show more respect for the primal forces within. Here, the Walkinshaw's malleable tractability reveals itself. Driven with due respect, it's just as mind-blowingly quick, but it's far more manageable and composed.

Intimate throttle response allows it to be driven hard without waking the traction control. The Walky's GTS underpinnings stand it in good dynamic stead, too. There's an element of understeer dialled into the chassis tune; push into a corner and it leans on the outside front, allowing the driver to scrub off some speed before feeding the power on.

I had figured on spending our first day wary of provoking the beast. Instead, I find myself upping the ante and pushing the Walky harder, deeper, faster. We climb the mountain on a tsunami of torque, leaving a concussive sound wave in our wake.

Even with the two-stage traction control in competitive mode, this car's tactility through wheel and throttle is such that it never unexpectedly breaks traction. For such a musclebound brute, it communicates like an Oxford scholar.

The HDT Blue Meanie is never far from the Walky's bumper, however, and as much as I'm buoyed by the latter's barrel-chested brilliance, I want to drive the car that makes 802Nm seem, well, under-endowed.

The HDT's SS-based interior is like chalk to the Walkinshaw's King Island cheese. Low-rent finishes and a monochrome information screen jar after the superior GTS-spec presentation. Not even custom-trimmed black-and-white leather sports seats can lift the interior vibe. It's one of the obvious trade-offs for a $30K lower entry price.

That aside, the distinctive Formula Blue exterior and white Aero wheels ensures the Blue Meanie turns more heads wherever we go. In Jindabyne, post-dusk shoot, any plans for our hungry crew to get the nose bag on vanish when half a dozen cars - including an HSV Coupe4 - descend on us, disgorging keen locals. In the most penetrating observation of the day, a motorcyclist remarks, "It looks lust like the VK."

The HDT's heavy-duty clutch lacks the feel of that in the Walky, and changing gears with the old-school Tremec T56 is like dragging a bar fridge through a rockery. Grumpy, recalcitrant and stubborn it may be, but you try copping almost 1100Nm everytime the throttle is stabbed.

If the Walkinshaw's brutal thrust is like a Wallabies crash tackle, the HDT adds the All Blacks for good measure. There's a raw brutality that initially makes it seem more ferocious. The booming exhaust can't match its rival for peak volume, but it out-growls and out-howls it. The Harrop 1900 supercharger shrieks balefully on full throttle, while the 6.0-litre V8 sounds like a pack of angry rottweilers.

The engine's lack of polish is obvious on throttle transition, but once in its stride, the HDT makes the Walky feel less, well, just less. Stepping back into the green machine will later feel like somebody's turned off two cylinders. Strange how 1078Nm can rearrange your sensibilities…

For all its brawn, the HDT is nowhere near as refined as the Walky. It's rude, abrupt, and coarse. To be fair, the car we're driving is a resurrected test mule. HDT actually built an atmo V8 for this test, but its paltry 400-ish kilowatts wouldn't have troubled the Walky, so this example was readied in a rush.

Despite its foibles the HDT is an enthralling drive, with depth that goes beyond its awesome performance. It's a real challenge to harness its raw power, but the car's skill set rewards application. The harder it's pushed, the better it responds and once I stop driving around the too-firm suspension and too-light steering, and push through them, the car delivers.

The SS steering, unchanged in ratio and assistance, is vague at seven-tenths on specially-fitted 19in Michelins, yet becomes chattier than the town gossip near the limit. The rear end is fidgety and nervous at pace, yet when I overcome my own nervousness on the throttle it squats, grips, and goes. It's as if the HDT is waiting to see if the driver is serious, and only then will it, too, get serious.

It's only when pulling into Jindabyne, some 300km after our last stop, that I realise how little throttle I've been using. There's simply no need to nail pedal to metal in either car because they both have so much to give. It's a guilty pleasure knowing each has more power and torque than I can ever reasonable use.

Despite big 73L tanks, both are showing almost empty, and near-identical fuel figures of 23L/100km betray just how much, erm… fun we've been having.

Sadly, about 200km into the drive back to Corryong with the test all but over the fun comes to an abrupt halt. The Meanie's over-worked traction control system gives up the ghost, sending the engine ECU into limp-home mode. Frantic phone calls to HDT reveal it is a known problem which they thought had been sorted. Efforts to troubleshoot it on the roadside prove futile and we're unable to run performance figures.

The Walky, however, does. At the wheel, with 1200 metres of deserted airstrip in front of me, and the supercharged V8 idling grumpily beneath my right foot, I'm poised to lay down some numbers. The engine bellows, the supercharger wails and the rear tyres shriek as they surrender grip. In an instant the engine slams into the 6650rpm cut-out. Second gear, white smoke wafts into the driver's window, and I ease off the throttle just short of the machine-gun cut-out. Slowly the tyres harness the epic grunt and the Walkinshaw lunges forward.

Third gear, and 100km/h blurs into 150km/h. The smoke clouds lift, the tyres finally stop painting black lines on the tarmac. Fourth gear, and 200km.h evaporates. The Walky charges relentlessly until, at an indicated 240km/h, we're out of revs and out of runway.

A second, cleaner, more ferocious launch sees numbers - the first independent figures for the Walkinshaw E2 Supercar - that are the quickest Wheels has ever extracted from a road-registered Commodore. Zero to 100km/h in 4.57sec is 0.6sec quicker than an HSV GTS. Zero to 400m takes 12.76sec; 0.8sec quicker than HSV's finest.

Roll-on acceleration stamps the Walky's dominance even more emphatically. It's almost a second quicker than a GTS from 80-120km/h in third, 2.5sec quicker in fourth and more than 3.0sec quicker in fifth. In moonshot sixth, the GTS takes 12.1sec, the Walky 7.3sec.

Days later, the rejuvenated HDT burbles away on the rubber-smeared tarmac of Sydney Dragway. Despite its epic 1078Nm, wheelspin isn't the issue. But a combination of clutch slip, a vague pick-up point and a baulky 'box are. The combo means shifts can take an entire second, and there are two cogs to swap from a standstill to 100km/h. The result? A disappointing 5.72sec 0-100km/h and 13.91sec over the 400m both fail to reveal the car's potential. The terminal speed of 182km/h is also slower than the Walky's 187km/h.

Then it happens again. The HDT comes to a shuddering halt. This time a faulty coolant temperature sensor has caused the V8 to go into 'safety mode' and it's game over.

It's a shame, because we've seen enough of the HDT to believe it has real potential to shake up Australia's muscle-car hierarchy. But in the final analysis, one car has done enough on road and track to convince us it's a worthy step up over an HSV GTS. That car is the Walkinshaw E2 Supercar.

But its rival here has unfinished business.