Callaway Cars has produced “Powerfully Engineered Automobiles” for 40 years now, and for 30 of those years they’ve mostly been enhancing the performance of what many consider the only true American sports car: the Chevrolet Corvette.

They started out by twin turbo-charging the 5.7-litre V8 in the 1987 Corvette C4, taking it from a stock 240 hp and 345 lb-ft of torque; to 345 hp and 465 lb-ft. This gain elevated the C4 from an OK sports car to a supercar to rival Europe’s finest.

As a bonus, Callaway products were fully covered under GM warranty, and could be ordered through many Chevrolet dealers—all you had to do was tick ‘RPO B2K’ on the options list.

But company founder Reeves Callaway wasn’t done yet. He wanted to take Callaway Cars to a point where it couldn’t be touched by anyone, and so started the ‘Sledgehammer’ program in 1988.

For this ultra-Corvette, Reeves came up with a motor backed by two Turbonetics T04b turbochargers producing 22 PSI of boost. The mill was good for 898 hp and 772 lb-ft of torque, and put the Sledgehammer in a category all its own—remember, the twin-turbo V8 in the rear of the Ferrari F40 was good for just 478 hp.

While Reeves had the motor worked out, he knew the standard C4 body was not going to handle the speeds he had in mind. That’s where a Canadian came in: Dr. Paul Deutschman. As part-owner of a design firm responsible for everything from hand dryers to concept cars, he got Reeves’ attention.

Dr. Deutschman designed an aero-body for the C4 that sliced through the air so cleanly, the car was able to nab a top speed of 410 km/h at the Transportation Research Center in Ohio on October 26, 1988. This cemented Callaway Cars’ reputation as makers of the fastest road cars on earth, as well as its partnership with Dr. Deutschman.

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Over the past 30 years, Dr. Deutschman has designed many models for Callaway, from mild facelifts to total re-skins.

The latest is the AeroWagen, a concept that started out as a late-night doodle. What Deutschman wanted was to give the Corvette C7 a slight change in visual character, something that would make people do double-takes. The Corvette is a victim of its own success, he reasoned: since there are lots, people hardly notice them.

Dr. Deutschman’s solution, first of all, is a nod to the classic “shooting brake” style of two-door sports wagons. But its kammback roof also improves aero, though Reeves notes the gain is so marginal, it’s not worth boasting about.

Due to its higher roof line, it also adds quite a bit more luggage space—while it hasn’t been measured yet, seeing a stock C7 hatch next to the AeroWagen’s makes the advantage clear. But for most clients, the AeroWagen conversion will be one made mostly for aesthetics, so their car stands apart from the thousands of C7s on the road.

It’s a simple conversion: all that’s required to turn a Corvette Coupe into an AeroWagen is to take the hatch off; remove the halo piece between the roof and rear hatch; replace it with a new halo piece (included); bolt in the carbon-fibre AeroWagen hatch (it’s less than a pound heavier than the standard hatch); and voila! your C7 has a new personality.

The AeroWagen still uses all the seals from the standard Corvette, so it is air-tight, there are no nasty squeaks and rattles, and it retains the soft-close mechanism for the hatch.

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The body prosthetic is only part of the story here, because Callaway also offers a substantial power boost for ’Vettes. For the 6.2-litre LT1 V8 in the Stingray and Grand Sport models, an Eaton 2.3-litre TVS supercharger takes output from the standard 460 hp and 465 lb-ft of torque up to 627 hp and 610 lb-ft.

Want more? For the 6.2-litre LT4 in the Z06, Callaway junks the standard car’s 1.7-litre blower and replaces it with an Eaton GenThree 2.3-litre TVS supercharger, so while the C7 Z06 leaves the factory with 650 hp and 650 lb-ft of torque – honestly, more than enough for most of us – Callaway’s tune takes power up to 757 hp and 777 lb-ft.

The standard Corvette hood couldn’t accommodate the larger charger, so Callaway created a new hood with a cut-out to let the supercharger peek through. This not only adds a ‘shaker-hood’ effect, it also allows for better air extraction, keeping the engine cool (early C7 Z06 models had an overheating issue). To further aid cooling, Callaway has installed a TripleCooled intercooler system.

It all sounds impressive on paper, but what’s it actually like? I was handed the keys to the only existing Callaway Corvette SC757 AeroWagen on the planet so I could find out.

Setting off from the National Corvette Museum in Bowling Green, Kentucky, I slowly weaved through the crowd assembled for the 2017 Corvette Bash. This eight-speed automatic-equipped tester (a seven-speed manual is also offered) made this easy—the torque just wafts you forward. For a car with big power figures, it’s remarkably docile at slow speeds.

On the thankfully empty back roads, I got to see what 757 horsepower can do. And as a short stab of the throttle reveals, that’s a lot.

Just twitch your right toe, and this car catapults forward as if hit from the back by a missile. Power delivery is instant, and relentless. It really has too much power to play with on public roads, even deserted ones—it’d be best to find a race track to really open it up, though sadly that wasn’t an option for me.

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What you can revel in is in short bursts of acceleration, and the noise exiting those double-D exhausts unique to Callaway. At slow speeds, it burbles along quietly; open the taps, and its growl will wake up the next county. This is not a car for not drawing attention.

The ride and handling is standard Corvette fare, which is no bad thing. Callaway says the C7 platform is so good, it didn’t need to do anything to it. It retains all the driving modes (Weather, Eco, Tour, Sport, Track) and suspension set-ups from Chevrolet, which vary depending on trim.

Standard Corvette wheels are, well, standard, but Callaway has its own wheels available, too. Tires on the tester were Michelin Pilot Super Sport P285/30/ZR19 for the fronts, and P335/25/ZR20 for the rears.

These strictly-summer tires provide a lot of grip, get up to temperature quickly, and hold on to the tarmac very firmly, even when they have to deal with 777 lb-ft of twisting force. Anything behind you won’t be after a few seconds—this car just grips and goes.

As for the rear view, the AeroWagen’s not as bad as you might imagine. Yes, the rear glass is small, but it’s quite upright, so looking through it is manageable. If you set your rearview mirror correctly, the rear pane almost looks like a full-frame lens.

Callaway has also given the AeroWagen a very slim rear lip spoiler, which doesn’t enter your rear view but helps clean the aero, allowing it to achieve a higher top speed.

Speaking of: the sprint from zero to 96 km/h is dealt with in 2.8 seconds, and the quarter-mile is covered in 10.5 seconds, at 211 km/h. Top speed is quoted at 333 km/h, easily making this the fastest wagon currently on sale.

The AeroWagen kit is available now from all global Callaway dealers (Canada has three). The cost is $14,990 US, which includes installation, an OEM color paint, two spoilers, halo bar, tempered glass, and AeroWagen badging.

If you want the ultimate AeroWagen, the SC757 package, Callaway offers that for $18,495 US. Add $2,990 US for the Callaway double-D sport exhaust; $6,280 US for the unique Callaway forged nine-spoke wheels in black chrome; plus the cost of a new Corvette Z06, which has a base price of $93,045 CDN.

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After all is said and done, you’re forking out just over $150,000 (plus tax) to park one in your garage. That does sound like a lot, but Lamborghini charges you about $700,000 to bring home an Aventador SV, with similar power and performance. Best of all, Callaway’s work is supported by General Motors, which means powertrain warranty is unaffected—three years or 60,000 km.

Will the AeroWagen make sense for the masses? No. It split the opinion of Corvette Bash attendees clean in half—some loved it, others were horrified. Callaway’s fine with that. He knew the AeroWagen won’t win everyone over, which’ll keep it relatively rare, adding to its mystique.

Thankfully, plenty of people do understand what makes Callaway Cars special, as the company sells several hundred vehicles per year, over 200 of which are Corvette-based.

What’s next from Callaway Cars? Work is underway to offer a road-going version of its GT3 race car, also designed by Dr. Deutschman. As for the performance specs that car’ll offer—we’ll just have to wait and see.