Forty years after the debut of the original GT500, Ford has once again teamed up with legendary Mustang tuner Carroll Shelby to create the 2007 Ford Shelby GT500. With the telltale Cobra emblem the only bit of brightwork on its blacked-out grille and a 500-horsepower, supercharged V8 stuffed under its hood, the Shelby GT500 is the most powerful road-going, factory-produced Mustang of all time. It's also one of the best performance buys for 2007, with a low-$40Ks price tag on the coupe version and a mid-$40Ks sticker on the convertible.

Unlike the late-1960s GT500, the 2007 GT500 doesn't rely on a massive 428-cubic-inch (7.0-liter) V8 to juice its rear tires. Rather, it uses a small-block, 5.4-liter V8 that's basically a detuned version of the engine from the GT supercar. On the GT500, supplier and cost concerns required the use of a wet-sump oil system (instead of dry-sump), a cast-iron block (instead of aluminum) and a "Roots-type" supercharger with 9 psi of boost (instead of an Eaton "screw-type" with 13.5 psi). But the GT's four-valve aluminum heads transferred over unchanged to the Shelby GT500, as did many smaller items, such as the piston rings and bearings. The result is 500 hp, 480 pound-feet of torque and a mid-4-second 0-60-mph estimate. Assuming the GT500 makes good on that claim, it would be the quickest car under $50,000.

To manage that horsepower boost, Ford's Special Vehicle Team (SVT) engineers reworked the Mustang's MacPherson strut front suspension, fitting stiffer shocks, higher-rate springs and an upgraded stabilizer bar. The solid-axle rear suspension uses upgraded springs as well, along with a Panhard rod to control wheel movement. Although a non-independent rear suspension might seem out of place on what's supposed to be a state-of-the-art performance car, the GT500 proves to be an agile and willing performer, whether on a racetrack or a remote two-lane road. Credit goes to the quick rack-and-pinion steering system, as well as the liberal traction control system, which allows for plenty of tail-out thrills. You can thank Carroll Shelby for the GT500's 18-by-9.5-inch wheels and 255/45 front and 285/40 rear Goodyear F1 tires: After driving a prototype, Shelby insisted on larger rolling stock to better manage the car's power and handling capabilities.

If there's a downside to the top Mustang's drivetrain, it's poundage. Ford lists the Shelby GT500's curb weight at 3,920 pounds in coupe form and 4,040 pounds for the convertible. That's about 400 pounds more than the equivalent Mustang GT. Although we wish this king of all Mustangs weighed less and had better interior materials, there's no denying the performance bargain the 2007 Ford Shelby GT500 represents for muscle-car fanatics. If you missed out on the original GT500, here's another opportunity to get in on the fun.

The 2007 Ford Shelby GT500 is sold as a four-seat coupe or convertible in a single trim level. Standard equipment includes 18-inch machined aluminum wheels with Goodyear F1 tires measuring 255/45ZR18 in front and 285/40ZR18 in back, a domed hood with functional heat extractors, a front air splitter and a ducktail-style rear spoiler. Inside, you'll find air-conditioning, leather-upholstered sport bucket seats with Cobra logos, six-way power adjustments for the driver, a 500-watt stereo with an in-dash CD changer, cruise control and full power accessories. The GT500 convertible also comes with a power-operated soft top. Both the coupe and the convertible have "GT500" side stripes, while the coupe also has racing stripes from nose to tail; Ford offers a stripe-delete option for buyers who prefer a stealth look. Options include an upgraded 1,000-watt sound system and Sirius Satellite Radio. A sunroof is not available on the coupe.

All Shelby GT500s are rear-wheel drive. Under the vented hood, you'll find a supercharged 5.4-liter V8 with an iron block and four-valve aluminum heads that provides 500 hp at 6,000 rpm and 480 lb-ft of torque at 4,500 rpm. A Tremec six-speed manual gearbox routes all that through a 3.31 limited-slip rear axle. No automatic transmission is available. Ford says the GT500 is capable of a 4.5-second 0-60-mph time at the test track and over 20 mpg on the highway.

Standard braking hardware consists of Brembo four-piston calipers squeezing 14.0-inch vented rotors up front and 11.8-inch vented discs clamped by two-piston calipers in back. ABS and traction control are included, as are front seat-mounted side airbags. Stability control and side curtain airbags are not available. Buyers should also note that the GT500 has no spare tire, just a temporary inflation kit.

With more power than any of the revered Shelby Mustangs of the 1960s, the 2007 GT500 offers performance that's nothing short of intoxicating. Just as its specs suggest, the Shelby GT500 moves out with exotic-carlike verve when you boot the throttle. Its deep well of torque, combined with a low-frequency exhaust bellow and high-pitched supercharger whine, make you want to access those 500 ponies again and again. Triple synchros in 1st and 2nd gear give the transmission a positive, crisp feel when swapping gears, and the overall driving experience manages to be both civilized and brutal, depending on where you position the accelerator pedal. Despite its 2-ton curb weight, Ford's GT500 is good for more than just a drag strip performance. Careful suspension tuning by Ford's engineers and a quick steering ratio make it feel surprisingly nimble through the turns, while a liberal traction control system allows for plenty of "slideways" action.

Shelby GT500 buyers can choose between an all-black and a black-and-red interior decor. The shifter knob is aluminum, and metallic trim is scattered about the cabin. An interior upgrade package provides stitched leather trim for the instrument hood and center console, along with aluminum covers for the pedals and an auto-dimming rearview mirror. Compared to the Mustang GT's gauge pack, the speedometer and tachometer have swapped places (the tach's on the right), and there's now a boost gauge and a message center. Additionally, the front seats have more lateral bolstering to hold you in during hard cornering. There's too much hard plastic for a car in this price range, but ergonomics are solid and you can carry a couple of children in the backseat. Trunk capacity measures 12.3 cubic feet.