They say those who fail to learn from history are doomed to repeat it, but Ford’s Special Vehicle Team has very carefully studied the Mustang’s history—specifically, the chapter on the 1967–70 Mustang Shelby GT500—and is gleefully set to repeat it, in spades, with no less an authority than Carroll Shelby himself adding his blessing and the use of his name. And when it comes to Mustangs, who in today’s car biz has more historical cachet? It was Shelby who raised the image of the original Mustang from an engaging all-American sporty car to a turnkey factory racer with the 1965 GT350 fastback. Then he followed up with the GT500, propelled by a big-block (7.0 liter) Ford 428 V-8 generating enough torque (420 pound-feet at 3200 rpm) to pull the skin of the earth measurably tighter when the driver tramped on the gas.
Tested: 2007 Ford Mustang Shelby GT500 Convertible
2006 Corvette vs. 2007 Shelby GT500
Mustang GT PPL2 vs. Mustang Shelby GT350
Fast forward to now, and at a glance Ford is reviving that same formula: a stronger engine in a Mustang fastback, delivering more power, more torque, better handling, and more visual intimidation. A little bit of history repeating, right? Well, yes. But that’s at a glance. Technology hasn’t exactly stood still since the last GT500 rolled out of a showroom in 1970, and even though this revival preserves a good old live-axle rear suspension—a mechanical tradition that has all but disappeared in current passenger cars—its mechanical credentials are fully contemporary. Not to mention seriously potent.
We brought you a preview of this new super-‘Stang in May, a quick thumbnail of the red prototype that was one of the stars of this year’s New York auto show. And having sat in and lusted after that show car, we immediately began pestering the Special Vehicle Team development crew, led by Hau Thai-Tang and chief vehicle engineer Jay O’Connell, for an early drive in one of the development cars.
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AARON KILEY
That led to a rendezvous at Ford’s proving ground in Romeo, Michigan, on a day in late April that ranged from damp to deluge. Not the right setting for getting acquainted with a muscle car on summer tires, but when you’re signed up for an exclusive first drive in the hottest production Mustang ever, you don’t quibble.
So what should you expect when this car rolls into showrooms next June?
Certainly, some traits are predictable. Tops on that list is hustle. With output of its supercharged engine forecast by the development team to be “over 450 horsepower and 450 pound-feet of torque,” the GT500 will be one quick pony. O’Connell predicts 0-to-60-mph times in the low-four-second range. Similarly, it’s not too surprising that this car responds to steering inputs a wink quicker than the Mustang GT and delivers considerably more grip and major-league stopping power.
What is surprising is the level of civility that goes with all of this. The GT500 is by definition a muscle car, but it’s not one of those remorseless brass bushing brutes that make their owners pay for visceral gratification with a relentless assault on their hearing and skeletal integrity. The 2001 SVT Mustang Cobra R comes to mind. In contrast, the GT500 should deliver enough compliance to make everyday driving a pleasure rather than a punishment, and we anticipate that interior noise levels may actually be lower than they are in a stock Mustang GT coupe.
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AARON KILEY
Let’s talk power. The heart of the GT500 is a supercharged 5.4-liter DOHC 32-valve V-8. If those specs sound familiar, it’s because they’re interchangeable with the description for the mid-engined Ford GT. But there are important distinctions. The GT V-8 is all aluminum with a dry-sump lubrication system, whereas the GT500 has an iron block and a wet sump. The GT engine is force-fed by a Lysholm screw-type supercharger; the GT500 will use an Eaton R122 Roots-type blower and an air-to-liquid intercooler, adding 10 psi to the intake system at peak boost.
O’Connell says the switch was dictated by availability, rather than price.
“The Lysholm unit is a little more expensive,” he says, “but the big problem was supply. They can’t make as many as we’re going to need. There are performance differences, too. The Lysholm type gives you a little more top end, and the Roots type is a little fatter in the midrange. We think owners will be satisfied with this setup.”
Judging by our weather-limited experience at Romeo and our test-track results with the 2003 SVT Mustang Cobra [C/D, June 2002], we concur. Power will be abundant, although O’Connell and his crew were still being cagey about specifics. Pressed on this issue, O’Connell said “between 450 and 500 horsepower—how’s that?” Our tech staff warmed up the calculators and figured a forecast of 475 horsepower at 6000 rpm. We may be low.
Big power isn’t much good unless it gets to the ground without excessive wheelspin, which is why the production GT500 will have a lot more rear tire than the New York show car, which hunkered over a set of 19-inch wheels wearing 255/45 tires. The initial production run of GT500s will roll on 9.5-by-18-inch wheels with sticky Goodyear Eagle Fl Supercar tires-255/45 front, 285/40 rear.
“We just couldn’t get the 255s to hook up,” says O’Connell. “Almost every run was going up in smoke.”
A pronounced forward weight bias—about 57/43, according to O’Connell didn’t help, either. Part of this is due to increased mass. The supercharged iron-block 5.4 weighs about 175 more pounds than the naturally aspirated 4.6 SOHC 24-valve aluminum V-8 in the Mustang GT. That factor, plus a bigger front-brake package, bigger wheels and tires, and other GT500 package elements, add up to a curb weight projected in the 3850-pound range versus 3575 pounds for the last Mustang GT we tested.
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AARON KILEY
But with the fatter Goodyears managing power delivered by a Tremec six-speed manual transmission and limited-slip rear end, O’Connell is confident the GT500 will sprint to 60 mph in “less than 4.5 seconds,” even with its tallish 3.31:1 rear-axle ratio. We expect that when we put the spurs to a test car early next year, a 0-to-60 number will come up in four seconds flat, and the quarter-mile will be 12.5 seconds at 116 mph. For perspective, those runs would be representative times for a C6 Corvette.
Other predictions: O’Connell forecasts a skidpad number of “0.91 or 0.92 g.” We think that’s a little conservative. Our last two C6 Corvette coupes [C/D, September and December 2004] produced identical 0.98 skidpad numbers. The GT500 will weigh in considerably higher, but it matches the Vette’s rear rubber and has even more contact patch up front. Accordingly, we expect to see at least 0.94 g.
Braking: The GT500’s 18-inch wheels will shelter huge 14.0-inch vented front rotors with four-piston calipers applying squeeze and 11.8-inch vented rear rotors. (The Mustang GT has 12.4-inch front rotors and 11.8-inch rears, all vented.) Given its Brembo braking system, bigger footprints, and stickier tires, we expect stops from 70 mph in less than 170 feet, which is, once again, Corvette territory. The front rotors on the GT500 show car were cross-drilled and vented. The production car’s brakes will lack cross drilling, which looks sexy but tends to produce cracks in hard use.
Handling: The GT500 has hefty front and rear anti-roll bars—a tubular 1.4-inch bar up front and a solid 0.9-inch rear bar and the spring rates and damping profiles have been adjusted to complement the massive power. There’s more roll stiffness, but it’s remarkable how supple the suspension manages to be, particularly with a live axle at the rear.
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AARON KILEY
The only negative dynamic comment in our notebook at the end of this brief time behind the wheel had to do with the power rack-and-pinion steering, which was quick (2.6 turns lock-to-lock) and accurate but felt a little light at high speeds. This was magnified by the absence of the production front air dam on our test mule. Unlike the early Mustangs, the GT500 is getting a lot of wind-tunnel time as part of its development, and O’Connell is intent on hitting the right balance between down-force and aerodynamic drag.
The test mule’s responses were colored by mild understeer—not too surprising, given the weight distribution and big disparity between the front and rear contact patches. And not unwelcome, since it makes the car’s responses predictable. Which is just what the SVT guys want.
“What we want is a little bit of steady-state understeer,” says Tom Chapman, SVT’s vehicle dynamics supervisor. “We don’t want to overdo it on agility, but we still want it to be fun to drive. Besides, we figure the driver can correct for understeer with his right foot any time he wants.”
Amen to that.
What else would you like to know? Price, perhaps? So would we. Like the matter of engine output, SVT will only offer a range of potential price points, from $36,000 to $40,000. The last SVT Mustang Cobra, with a mere 390 horsepower, cost $35,485. Our guess for this one is $39,000. Like the Mustang GT, that would be a tough-to-top performance buy, judging by our acceleration, braking, and skidpad forecasts. We’ll be waiting for your letters.
Carroll Shelby will always be remembered for his Cobra roadsters, but it was the GT350 and GT500 Mustangs that really filled 01’ Shel’s chili pot during the late ’60s—particularly the GT500. Although it was ponderous compared with the hard-edged GT350 of ’65 and ’66, the GT500 advanced an essential truth of the emerging U.S. sporty-car market: Americans liked speed, but not at the expense of comfort. This was the heyday of the big-inch V-8, when the U.S. industry was busily making torque junkies of us all, and that’s precisely what the GT500 delivered—lots of low-end grunt from a low-tech Ford 428 V-8, which was almost $1000 cheaper than the more potent 427 made famous by the Cobra.
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AARON KILEY
Most GT500s came with an automatic transmission, and if they weren’t pure sports cars, they were easy to live with. The GT500 made its debut for the 1967 model year with a price of $4195 and immediately outsold the $3995 GT350. Our road test in February 1967 characterized it as “an adult sports car,” noting that compared with the early GT350 “all the viciousness had gone out of the car, without any lessening of its animal vitality.” We quoted Shelby as calling it “the first car I’m really proud of.” In the next couple of years, both models acquired more and more comfort and convenience features, including convertible versions, moving steadily closer to the passenger-car mainstream. The last Shelby Mustangs were built in 1969, although some were sold as 1970 models. In all, just over 6500 GT500 and GT500KR (for “King of the Road”) cars were built. Recent GT500 auction prices, per Keith Martin’s authoritative Sports Car Market, were more than $90,000. This pristine 1968 model is owned by John Gribbel III, who lives in Palm Beach Gardens, Florida, when the weather is too severe back home in Melvin Village, New Hampshire.
Specifications
SPECIFICATIONS
2007 Ford Mustang Shelby Cobra GT500
VEHICLE TYPE front-engine, rear-wheel-drive, 4-passenger, 2-door coupe
ESTIMATED BASE PRICE $39,000
ENGINE TYPEsupercharged and intercooled V-8, iron block and aluminum headsDisplacement 330 in3, 5409 cm3Power (C/D est)475 hp @ 6000 rpmTorque (C/D est) 450 lb-ft @ 3750 rpm
TRANSMISSION 6-speed manual
DIMENSIONSWheelbase: 107.1 in inLength: 188.0 inWidth: 73.9 inHeight: 55.7 inCurb weight: 3850 lb
PERFORMANCE (C/D EST)Zero to 60 mph: 4.0 secStanding ¼-mile: 12.5 sec @ 116 mphTop speed (governor limited): 160 mph
FUEL ECONOMY (C/D EST)EPA city/highway: 13/21 mpg
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