Admit it. You sat on your hands when the original 1965-'70 Shelby Mustangs went on sale. And you did it again when those cars were still going for less than $30,000 a few years back. Now you're just another one of those annoying types, sitting around telling "coulda-woulda-shoulda" stories. Well, my bitter friend, you've got at least one more chance to buy a sub-$50,000 pony car blessed by the man responsible for Ford's original Cobra, GT40 and GT500. The 2007 Shelby GT500 is about to enter a showroom near you, and it's easily the most powerful and best-performing factory Mustang ever built.

The boys at Ford's SVT reunited with Carroll Shelby to create this super Mustang, and if you think it bears more than a passing resemblance to the 1968 GT500KR, you're right (which we feel is a good thing, by the way). But unlike the original GT500 nameplate (a random number that came from counting off steps in Shelby's 1960s-era workshop), this Mustang's moniker has a basis in fact. Yup, the 5.4-liter V8 under that vented hood makes an honest 500 horsepower, along with 480 pound-feet of torque.

There's a little Ford GT in every GT500 we build
Those figures aren't too surprising when you consider that much of the GT500's engine comes straight out of the Ford GT parts bin. The GT used an aluminum block with a dry-sump oil system and an Eaton "screw-type" supercharger creating 13.5 psi of boost. For the GT500, supplier and cost concerns required the use of a wet sump, cast-iron block and "Roots-type" supercharger with 9 psi of boost. But the Ford GT's four-valve aluminum heads transferred over unchanged, as did many smaller items, such as the piston rings and bearings.

Directing that power is a Tremec six-speed manual transmission featuring dual 215mm cerametallic clutch plates. The cerametallic coating can withstand extremely high temperatures, and the dual-disc design increases the clutch engagement surface area without requiring free-weight leg training to operate smoothly. This is exactly the same unit Ford used in the 2005 Grand Am Mustang — the car that won last year's championship its first year out — so they figure it's been adequately stress-tested for the GT500's street duty.

As those engine numbers suggest, the GT500 moves out with exotic-carlike verve when you boot the throttle. Its deep well of torque, combined with a low-frequency exhaust wail and high-pitched supercharger whine, make you want to access those 500 ponies again and again. The 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. Ford expects the car to pull zero to 60 in the mid-4-second range, a number that jibes with our internal accelerometers.

Heavy metal, capable cornering
If there's a downside to this drivetrain, it's poundage. Ford lists the 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. Much of that bulk comes from the drivetrain, which is about 350 pounds heavier than the GT's. This also means the weight gain is largely on the front half of the car, suggesting front-end flabbiness compared to the base Mustang's nimble character. Yet we're happy to report that Ford didn't sacrifice the GT500's cornering capabilities for the sake of straight-line acceleration.

The independent MacPherson strut front suspension is reworked with stiffer shocks, higher spring rates and an upgraded stabilizer bar. The solid-axle rear suspension uses upgraded springs as well, along with a Panhard rod to control wheel movement. Suspension settings on the GT500 convertible were left a bit softer to reduce chassis flex, but happily both Shelby models (as well as all 2007 and later base Mustangs) benefit from chassis upgrades in the firewall, transmission tunnel and frame rails.

Our seat time in the GT500 included public road motoring as well as racetrack flogging, and it was at the track where we confirmed the Shelby's agile and willing demeanor. The confident and quick rack and pinion steering system, along with a liberal traction control system, effectively masked the car's 2-ton curb weight while allowing for a healthy bit of "slideways" action (think C6 Corvette's "Competition Mode"). Slowing the car was similarly worry-free, with Brembo four-piston calibers squeezing 14-inch vented rotors up front and 11.8-inch vented discs — clamped by two-piston calibers — in back (still more donor parts from the Ford GT program).

Mr. Shelby says, "Make it so"
A specific upgrade directed by Carroll Shelby himself had to do with the GT500's tire size. After driving a prototype, the Texas chicken farmer insisted on larger rolling stock to better manage the car's power and handling capabilities. One look at the car's 18-by-9.5-inch aluminum wheels and Goodyear F1 rubber suggests he got his way. The 255/40 front tires contrast against the larger 285/40 rear tires to give the GT500 both functional and visual appeal.

Pimp my pony
Other bits of eye candy include the Shelby Mustang's larger front air intakes, wide Le Mans-style body stripes and requisite Cobra and GT500 emblems. Inside the cabin, buyers can stick with the basic charcoal black treatment or add red inserts to the seats and doors. All models feature a black leather-wrapped steering wheel and shifter with contrasting red stitching, but an optional Performance Interior Trim Package will further dress up the instrument panel, center console and door armrests with leather inserts. This package also comes with an electrochromic, auto-dimming rearview mirror and aluminum pedal covers. Considering the $42,975 starting price for a GT500 coupe ($47,800 for the convertible) we'd expect higher-grade materials on the door panels and dash, but at least buyers will have the option to somewhat upgrade the interior's look and feel with this package (for an added cost).

Forty-three grand may seem a bit steep for a Mustang, but remember: This car's performance pedigree suggests it will easily challenge Corvettes and M3s, both of which cost substantially more. Of course, if you're still not convinced, you could always let yet another Shelby Mustang pass you by.

Just don't expect us to put up with any more "coulda-woulda-shoulda" stories.