For the first time in its decade-and-a-half of production, Chevrolet's Corvette--billed as "America's only true sports car"--is being challenged for the title. Shelby American's G.T. 500 Mustang-based sports fastback has all the earmarks of a "purist" type sporty car with a just-right combination of comfort and convenience features.

Following Shelby American's announcement of a 428ci V-8-engined GT, we were skeptical if this car would be suited for street duties. We've driven many small cars with huge engine transplants, and somehow they always seemed to lack tameness during regular operation--unless regular operation was a full-throttle run down a 'strip. We found out, though, just how wrong we were after depositing ourselves behind the custom wood steering wheel of an air-conditioned G.T. 500 with Cruise-O-Matic transmission.

We could hardly believe its smoothness in bumper-to-taillight traffic and had difficulty realizing it was built by the same people who used to peddle a rough-riding, hard-steering Mustang fastback with Bunyanesque brake pedal and an engine that would outshout a John Deere tractor.

In view of this, we arranged for an even hairier G.T. 500, and also set up an equally equipped Corvette to see if there really was a challenge.

The basic Shelby G.T. 500 is a true sophisticate compared with earlier cars built by the famous Texan. There was a brief period when the Ford Cobra, also built by Shelby, was thought to be a fair and equal competitor to the Vette, but a too-high price and rather impractical design for a street-destined car put it out of contention. Chevy has cause for some worry from the G.T. 500, though. There's more room inside, and it's easier to drive in traffic. There's a civilized luggage compartment that's accessible from the outside, and there's at least the same measure of racy styling. The G.T. 500 runs quieter, and in general is a more practical car for everyday use.

The Corvette can't be sold short, though. Even in stock condition, it outruns the G.T. 500 by a solid 0.7-second in the quarter-mile, stops in less distance from any speed, is easier on gas, and exhibits noticeably better workmanship throughout.

The Vette started life back in 1953--before the world or Ford Motor Co. had ever heard of a car called the Mustang--and was then equipped with an impotent six-cylinder engine and fiberglass body. The 'glass body has remained, but the sixes were dropped two years later and the car since then has steadily climbed higher and higher in the esteem of performance addicts. Equipping the Corvette with a 427ci engine was a natural move for Chevrolet, and for the past two years this version has been the image-maker of the line. Previous editions of the 'glass-bodied car were offered with as much luxury built in as speed and performance, and we remember a statement concerning Corvette sales cutting into Cadillac. The luxury is still there, but a hard ride comes with it, so we doubt if Cadillac is still worried.

There's more potential for making the Corvette a hard runner than there is the G.T. 500. The 428ci V-8 in the Shelby car is too heavy for serious work, and it has a rather restricted breathing system compared with the 427ci Chevy V-8. Called "porcupine" by Chevy engineers, the valve layout of the Vette engine is more ideally suited to getting big charges of air/fuel mixes into the combustion chamber, and the head configuration above the chamber is a "semi Hemi" type, similar to early Chryslers.

Weight distribution is better on the G.T. 500, with 56.4 percent being carried on the front wheels. The two total out almost equally, but so much of the Corvette is the front, that it is distinctly nose-heavy. This characteristic is abruptly apparent when one attempts to leave the line under hard throttle, or when you bring it around a sharp bend while applying power. The rear end becomes frighteningly "light."

Starting with two basic cars, more is standard equipment on the G.T. 500 than on the Vette, but there's some chicanery involved. For the base price of $4,195, a G.T. 500 buyer gets the 428 engine, front-disc/rear-drum brakes, full instrumentation, a four-speed transmission, and all the modified bodywork that goes into making a G.T. 500 the distinctive-looking car it is. He also gets the beefed-up undercarriage, which includes stiffer springs, adjustable shocks, and modifications to front suspension to make it corner more flatly. On top of this, though, he must buy power brakes, power steering, integral rollbar with inertia-reel shoulder harnesses (the best we've ever seen), and a fold-down rear seat. This comes to a total of $264.77 before he ever starts ordering a radio, air conditioning, or whatever else he may choose. This is sort of like selling a car without seats and a steering wheel, but putting them on the car at the "buyer's request." All G.T. 500s are built with this batch of options, which are called "standard equipment," but which really are not.

For the base convertible price of $4,327.50, a Corvette buyer has all options still in front of him, with nothing mandatory except making the payments. The standard Corvette includes a 300hp, 327ci V-8, either a soft folding top or fiberglass lift-off type, and all instruments and gauges along with a three-speed all-synchro gearbox. From there the owner can choose any one of four optional engines and two four-speed manuals or a Powerglide transmission.

The primary function of an automobile, no matter what type it is, is to carry passengers wherever they may want to go. The G.T. 500 does this better than the Corvette. It has more room inside for people and packages, and will carry four adults for a short time or two children for a long time without complaints. The fold-down rear seat can become a parcel counter when only two are aboard, and the trunk bulkhead swings up for stowage of skis and the like.

The G.T. 500 is much easier to drive in traffic, as it's not as low as the Corvette, and it's not as ticklish to keep running at slow speeds. That big 435hp Vette engine likes to work hard, and when it's in bumper-to-bumper traffic, it objects.

The ride on city streets is much better in the G.T. 500. There's very little bumping around, whereas the position of the driver in the Corvette is very close to the rear wheels, and any rebound action from them is strongly noticed by the man at the wheel.

Vision in the two cars is almost equal, but still not excellent. We liked the '66 Shelby GTs for their rear-quarter windows, but construction differences on the '67 Mustang prevented their continuance on Shelby's version. Corvette convertibles have blind rear quarters, too, and the lift-off 'glass top isn't much better. The fastback model allows full vision.

We liked the interior layout of the G.T. 500, but it doesn't have the Maserati look of the Corvette. The Vette has all necessary instruments right in front of the driver, and all within a few inches reach. The Shelby car has the speedometer and tach right in front of the pilot, but the amp and oil-pressure gauges (Shelby additions) are positioned centrally below the radio. It's not hard to see them, but they're not as readable as in the Corvette, nor are they in a direct line of sight with the road.

The really impressive points of the G.T. 500's insides are its great-feeling wood steering wheel and the integral rollbar with inertia- reel shoulder harnesses. The wheel is one of the most comfortable we've ever had our paws on, with a smooth lacquered finish and a genuine "sporty" look. Shoulder harnesses can be cumbersome, and restrict the normal movements of the driver, but not so in the G.T. 500. They fit around you like suspenders. The inertia retractor in the rollbar allows slow movement, but quickly holds you against any sudden jerk or action. You learn to be leisurely when reaching for the cigarette lighter.

The Vette spare is in a panel below the rear underside that, in the rain, may give AAA reason to upgrade its rates. There is room for perhaps two suitcases behind the seat.

It takes a while to get used to the stiff-riding Corvette, and the low driver position. Once we became oriented, however, we went along with the "true sports car" claim. The Vette is a lot of fun, but discretion must be used in driving around town. It's awful easy to bound past speed limits unknowingly.

Less of an all-out sports car, the G.T. 500 is more at home on the street than on the track. We received many more comments on the 500's styling than we did on the Chevy sportster's, but this can be attributed as much to its being new as anything.

Our forecast of how the cars would compare on the track turned out to be accurate. We were highly impressed with the solid-as-a-rock cornering of the G.T. 500, and its agility in quick turns. It ran impressively in acceleration tests, staying straight when the tires were spun, and it stopped quick straight. But even with this good performance record, it fell short of outrunning and outmaneuvering the Corvette.

Unfortunately, Chevrolet couldn't find enough room under the fender wells for a tire comparable to the E70-15 nylons standard on the G.T. 500, so it suffers in this department. Standard 7.75x15 rayon tires are fitted, and this makes cornering and starting difficult. Gobs of wheelspin are all that result from a high-rpm start, but proper feathering of the gas pedal will help. The independent rear suspension gets an unfair shake when these regular tires are installed, and the rear end tends to leave the course when the car is pushed. Hooking up tires equivalent to the Speedway 350 Goodyears on the test G.T. 500 solved the Corvette's problems quickly. The potential is built in, but anyone desiring to put a Vette in proper handling form will have to start with a set of tires and the realization that lock-to-lock cornering will be slightly restricted.

It's quite a foe that Shelby's G.T. 500 has taken on, but not an unconquerable one. The Corvette is designed as a sports car, and that's what it is. It suffers somewhat as a street machine, but in no way is it reminiscent of early English sports cars with fold-down windshields and side curtains.

The 500 has more passenger-car than sports-car feel, but this could hardly be helped, as the Mustang from which it stems has this quality. With a bigger engine (horsepower, not displacement), it would be close to the Corvette's acceleration times.

The two cars are apart yet fairly close. Shelby American built the G.T. 500 with the idea of getting more customers for street-type vehicles than they could with the race-oriented G.T. 350s of the past. Oddly enough, this is what Chevrolet's theory has been too. They've been building a "hot" car for the street that would qualify for competitive use. Shelby's just reversed the game and taken a competition-type car and turned it into a street machine. Both gain in some respects and suffer in others from the compromise.

Sting Ray at a Glance

  • Easily the most powerful production car made
  • Designed and built as an all-out sports car, yet fairly suitable for everyday use
  • Stiff-riding suspension makes around-town jaunts and long trips uncomfortable on the torso, but free of handling problems
  • Styling exhibits a "going" look, even when standing still
  • Practiced drivers can feel safe at all speeds and in all conditions, due to four-wheel disc brakes, quick steering, and good stability

How the Car Performed & Specifications
Acceleration (two aboard)0-30 mph 2.5 sec/0-45 mph 3.8 sec/0-60 mph 5.5 sec/0-75 mph 7.5 sec
Time and distance to attain passing speeds 40-60 mph 2.1 sec, 151 ft/50-70 mph 2.0 sec, 172 ft/Standing-start quarter-mile 13.8 sec, 104 mph
Best speeds in gears at shift pointsFirst: 65 mph @ 6,500 rpm/Second: 87 mph @ 6,500 rpm/Third: 112 mph @ 6,500 rpm/Top Speed: 143 mph @ 6,500 rpm/Mph per 1,000 rpm: 22.0
Speedometer errorCalibrated speedometer 30 45 50 60 70 80/Car's speedometer 28 44 49 58 67 77
EngineOHV V-8
Bore and stroke (in)4.251 x 3.76
Displacement (ci)427
Torque (lb-ft)460 @ 4,000 rpm
Horsepower435 @ 5,800 rpm
Compression Ratio11.0:1
CarburetionThree two-barrel Holleys
TransmissionOptional four-speed manual, floor-mounted lever, all forward gears fully synchronous; ratios of 2.20 in First, 1.64 in Second, 1.27 in Third, and 1.00 in Fourth
Final Drive Ratio3.55:1
SuspensionIndependent front, single-lateral-arm type with coil spring, tube shock, and spherically jointed steering knuckle at each wheel; fully independent rear with fixed differential, transverse multi-leaf spring, lateral struts, and universally jointed axle shafts; tube shocks at each rear wheel
SteeringOptional linkage-type power assist, with semi-reversible recirculating ball nut; 17.6:1 overall gear ratio; turning diameter--39.9 feet, curb to curb; number of turns lock to lock--2.92
WheelsShort-spoke disc steel, 15x6
Tires7.75x15 rayon
BrakesFour-wheel hydraulic, caliper disc operated by dual system; power optional; diameter of disc front and rear--11.75 in; effective lining area--78.1 sq in
Fuel Capacity20 gal
Mileage range9.0-12.0 mpg
Body and frameSeparate construction; all-welded, full-length, ladder-constructed frame with five crossmembers; fiberglass body
DimensionsWheelbase--98.0 in; Track front 57.6 in, rear 58.3 in; overall length--175.1 in; width--69.6 in; height--49.8 in
Usable trunk capacity8.1 cu ft
Curb weight3,340 lbs

G.T. 500 at a Glance

  • Eye-catching styling is product of good judgment in restyling already good-looking Mustang fastback
  • Well-suited for street duties, but refinements needed to make it an all-out champ on the track
  • One of the most comfortable cars for touring we've driven, but in-and-out from driver's seat is a tight fit
  • Fiberglass additions would benefit from tighter quality-control inspection
  • Shoulder harness impressed us to the point of dissatisfaction with all others

How the Car Performed & Specifications
Acceleration (two aboard)0-30 mph 2.9 sec/0-45 mph 4.4 sec/0-60 mph 6.2 sec/0-75 mph 9.5 sec
Time and distance to attain passing speeds 40-60 mph 2.6 sec, 190 ft/50-70 mph 3.0 sec, 264 ft/Standing-start quarter-mile 14.52 seconds, 101.35 mph
Best speeds in gears at shift pointsFirst: 51 mph @ 5,500 rpm/Second: 68 mph @ 5,500 rpm/Third: 93 mph @ 5,500 rpm/Top Speed: 120 mph @ 5,500 rpm/Mph per 1,000: rpm 21.1
Speedometer errorCalibrated speedometer 30 45 50 60 70 80/Car's speedometer 27 40 45 55 64 72
EngineOHV V-8
Bore and stroke (in)4.13x3.984
Displacement (ci)428
Torque (lb-ft)420 @ 3,200 rpm
Horsepower355 @ 5,400 rpm
Compression Ratio10.5:1
CarburetionTwo four-barrel Holleys
TransmissionFour-speed manual, floor-mounted lever, all forward gears fully synchronous; ratios of 2.32 in First, 1.69 in Second, 1.29 in Third, and 1.00 in Fourth
Final Drive Ratio3.50:1
SuspensionIndependent front with coil spring and ball joints, modified for flatter cornering, 0.94-in (diameter) front stabilizer bar; straddle-mounted HD rear axle, single unit, suspended with longitudinal four-leaf springs with special rebound dampers to control rear spring windup; preset adjustable shock absorbers at each wheel
SteeringRecirculating ball and nut, linkage-type power assist standard; 16:1 overall gear ratio; turning diameter--37.16 feet, curb to curb; number of turns lock to lock--3.74
WheelsShelby steel, 15x6.5
Tires"Speedway 350" Goodyear low-profile, four-ply nylon; E70-15 140-mph rated (standard)
BrakesDual-system hydraulic; front disc/rear drum with power assist and high-speed linings on disc caliper; diameter of front disc--11.3 in; diameter of rear drum--10 in; effective lining area--191.0 sq in
Fuel Capacity16 gal
Mileage range7.6-14.6 mpg
Body and framePlatform-type unitized construction with reinforced floor side members and export front-end reinforcement
DimensionsWheelbase--108.0 in; Track front 58.0 in, rear 58.0 in; overall length--186.6 in; width--70.9 in; height--51.6 in
Usable trunk capacity5.1 cu ft
Curb weight3,360 lbs

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