Jerry Heasley
January 12, 2007

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It seems there's always something special coming out of Unique Performance in Farmers Branch, Texas.

Several months ago, we spied a yellow '68 convertible in the back of its shop. It was definitely unique with "GT500SR" in the lower rocker-panel stripes on the front fenders. We knew right away the 500 designation meant big-block in Shelby lingo, and we have come to know that SR stands for street/race in Unique's continuation business.

So, what we were staring at had to be a really hot big-block Shelby continuation convertible. Obviously, Unique was looking back at Shelby history and moving up through the model years to continue other Shelby lines of the '65-'70 era.

Later, Unique's president Doug Hasty told us, "Our GT500SR is based on the requests of customers. They asked us to look at doing something similar to what we've done with the 350SR and the 500E." Shelby didn't come out with a convertible until the '68 model year. Thus, the GT500SR is catalogued as a '68, although '67 models may be used because the basic body style is the same.

To seasoned collectors, the sight of an R-model-style fiberglass front apron replacing the stock bumper is an odd sight on a '68, but it certainly pushes across the high-performance message. The SR in the 500 series is a no-nonsense build. Its performance is the car's entrance into the Shelby legacy, and we're talking 21st-century technology here. The 500 designation means big-block. Carroll would have it no other way than his own aluminum-block 427, an ageless torque monster based on the vintage FE design, or as Hasty put it, "This is the way Carroll would have built an SR in 1968 if he had the ingredients we have today."

Luckily, the hood was open when I first spied the car in the shop. The FE-series Shelby 427 aluminum big-block looked downright wicked with the DC&O electronic fuel injection. By design, it's easy to mistake this setup for a rack of Webers, but old-time carburetors can be fussy, especially on the street. Modern fuel injection allows the tuner to make the best of air/fuel ratios for maximum horsepower.

How hot is the 427 fuelie? The spec list Unique handed us reads 525 hp. Apparently, this number is conservative. It's also the rating with a carbureted 427, which is the base engine. With either carbs or the optional fuel injection, "You're looking at every bit of 600-625 horses," Hasty tells us.

Planting this amount of power to the rear wheels of a '68 Mustang, which is rather flimsy in its stock configuration, requires a considerable amount of modification. Like every Unique-built continuation Mustang, the GT500SR is drastically modified. The suspension is similar to the Eleanor and the Super Snake. Factory stamped-steel control arms won't stand up, so Unique replaces them with TIG-welded tubular uppers and lowers featuring 4130 chrome-moly rod ends and Teflon inserts. Steering is modern rack-and-pinion.

Although an original 9-inch rearend would be tough enough, it doesn't fit Unique's coilover rear suspension that features laid-down springs and shocks as well as upgraded leaves that fit tires as big as 315/35s. The Currie Tru-Track differential is basically a 9-inch highlighted by a big-bearing housing, a short yoke, and a nodular case capable of planting 900 hp to the pavement.

Making mega-horsepower is one thing. Utilizing mega-horsepower in a 40-year-old Mustang is quite another. No manual four-speed from the Ford arsenal of the '60s could take 600 horses, so Unique engineered new motor mounts and a transmission crossmember to retrofit a Tremec TKO 500 five-speed.

Even without the Shelby heritage, series-built Mustangs of such brute power command instant respect. Serialized with the Shelby blessing, these continuation Shelbys will be registered with the Shelby American Automobile Club for their latest World Registry.

Hasty said Shelby enthusiasts and collectors are the main clientele for these cars, some of whom have "a stable full" of Shelby vehicles already. The Unique Web site lists "investments" starting at $149,000 for the GT500SR. For this amount, you get a Shelby continuation vehicle that is basically a turnkey supercar, ready to take to the track or drive on the street.

Doug told us Unique is working on a '69 Shelby continuation that will also be part of the GT500SR series, so the GT500SR will encompass '68 through '70 models. They will be available as convertibles, as seen here, and as fastbacks, which we have not seen.

It will be interesting to see how Unique and Shelby put together the continuation '69 series in a GT500SR, including a new performance look with an R-model front apron replacing the original's chrome front bumper. So, we have more surprises ahead.

Yes, it seems there's always something special coming out of Unique Performance in Farmers Branch, Texas. We can't wait for the next surprise.

Collector Interest

We're starting to get a feel for the rarity of the continuation Shelbys. Production is limited to 475 for the Eleanor series, 400 GT500E fastbacks and 75 GT500E Super Snakes, which is already sold out.

Hasty originally set the GT500SR production at 500 units for all three model years and body styles. "More than likely, I'll cut production rather than keeping the number way up there," he tells us. "We may bring production numbers way down."

All of the Unique-built continuation Shelbys are licensed by Carroll Shelby and will be listed in the Shelby American World Registry. When production ends, we'll have another unique chapter in the history of Shelby and another specialty group of Shelby Mustangs to chase.

Production totals will be interesting when the Shelby continuation buildout ends. Unique's total could be under 1,000 units. That would be a small part of the total Shelby production from 1965 through 1970, which was 14,358.

Tech Specs

The Unique Performance Shelby GT500SRs are based on original '67-'70 Mustangs, which are stripped to a bare shell, then rebuilt with the latest technology. Both coupe and convertible versions are available, and each car receives a Shelby VIN.

Shelby Performance aluminum 427 FE engine, 525hp
DC&O electronic fuel injection*

Tremec TKO five-speed
Currie 9-inch positraction Tru-Trac differential
31-spline axles
3.25:1 final drive ratio

Carroll Shelby embroidered bucket seats, vinyl
Carroll Shelby embroidered bucket seats, leather*
G-Force five-point quick-release harness, includes horizontal bar
Shelby signature gauges
200-mph electronic speedometer
15-inch custom steering wheel
Old Air Products Hurricane A/C system
CAE sound-dampening package*
Sony stereo with CD player
DVD system*
8-disc CD changer*
Wheels & Tires
Shelby wheels, 17-x8-inch with 245/40ZR17
performance tires
Custom Shelby rear wheels, 17-x9.5-inch with 275/40ZR17 tires*
PSE wheels, 17-x8-inch front/17-x9.5-inch rear with 245/40ZR17 and 275/40ZR17 tires*
PSE wheels, 17-x8-inch front/17-x11-inch rear with 245/40ZR17 and 245/40ZR17 tires; rear tubbing*
Spare Shelby or PSE wheel with mounting bracket*

Shelby emblems
SC Cobra-style gas lid
2 1/2-inch side-exhaust system

Fuel System
Electric fuel pump
High-performance fuel filter
Fuel cell, 16 gallons
Fuel cell, 22 gallons*

Unique Suspension Products' power rack-and-pinion steering
Baer Tracker bumpsteer adjustable tie rods

Front: 13-inch slotted, cross-drilled rotors
Rear: 12-inch slotted, cross-drilled rotors
Adjustable proportioning valve
Vented air ducts to brakes

MSD ignition control and coil
Trunk-mounted battery

Headers with ceramic coating
Dual 2.5-inch with H-pipe
Spin Tech 2.5-inch aluminum mufflers

Aluminum cross-flow radiator
16-inch electric cooling fan
Electric fan-temp switch

Unique Suspension Products subframe connectors
Unique Suspension Products center bolt-in section
Unique Suspension Products shock-tower bracing
Driveshaft safety loop
Rollbar, four-point

Unique Performance Products front coilovers
Koni rear gas shocks
Shelby-style traction bars
Unique Performance Products rear coilovers*

* Optional upgrade