Ford Mustang 1967 Shelby GT500 – 390 V8 Mustang Fastback – Test Drive

A big-block 1967 Mustang fastback can be one of two very different cars — a genuine Shelby GT500 or a standard 390 GT that looks nearly identical from across a parking lot. The difference comes down to a 428 Police Interceptor V8, a handful of interior details, and a VIN that either matches Shelby American’s registry or doesn’t. Read on to find out what actually separates the two.

Say “Shelby GT500” to any Mustang die-hard and their mind jumps straight to one number: 428. That’s the Police Interceptor big-block Shelby dropped under the hood in 1967, and it’s the engine that separates a genuine GT500 from every other big-block fastback Ford built that year — including 390-powered cars that get mistaken for Shelbys more often than owners probably like to admit. A beautiful 1967 fastback with a big-block rumble is a great car no matter what badge is on the fender, but the difference between a 390 GT and a real GT500 is the difference between a fast Mustang and one of the most famous muscle cars Ford ever built. So which one are you actually looking at?

What Actually Made a GT500 a GT500

Shelby’s 1967 GT500 came standard with a 428 cubic-inch Police Interceptor V8 fed by twin 600-cfm Holley four-barrels on a medium-rise aluminum intake, a setup Ford officially rated at 355 horsepower and 420 lb-ft of torque, numbers most enthusiasts and period road testers believe were sandbagged to keep insurance companies happy, with real output likely closer to 400 horsepower. The GT500’s 0-60 time of roughly 6.2 seconds backs that up. That’s a very different animal from the FE-based 390 GT engine that powered plenty of standard 1967 Mustang fastbacks. Ford also fitted the GT500 with staggered rear shocks to help tame wheel hop under hard acceleration, a small but telling engineering detail Shelby folded straight into the production line.

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Why the Two Get Confused Constantly

Both engines are FE-family big-blocks, both came in fastback bodies, and both make a genuinely great noise through dual exhaust, which is exactly why casual observers, and more than a few sellers, blur the line between a standard 390 GT fastback and Shelby’s 428-powered GT500. The real tells live in the details: Shelby’s fiberglass nose and hood, the wider taillight panel borrowed from the Cougar, the roll bar, and of course the VIN and door tag that confirm whether a car actually left Shelby American or just left a Ford assembly line with a big-block and a fastback roof.

The Real Value Is in the Paper Trail

Whether this particular fastback turns out to be a true GT500 or a well-built 390 GT tribute, the way to know for certain is the same either way: a Marti Report or Ford data plate decode, checked against Shelby American’s own registry for genuine GT500 production. Real GT500s carry a premium that a standard fastback simply can’t touch, which is exactly why documentation matters more on a car like this than on almost anything else from the muscle car era.

Shelby’s 1967 Lineup Expansion

In 1967 Shelby broadened the lineup beyond the small-block GT350 by adding the GT500, giving buyers a genuine big-block option for the first time under the Shelby banner. The GT350 stuck with a high-revving small-block through 1967, so the GT500 filled a gap Shelby’s cars hadn’t touched since the original 289 Cobra days. Ford’s newly widened ’67 body, with a bigger engine bay and reworked front clip, was built partly with that big-block swap in mind, which is why the GT500 conversion feels so factory-integrated rather than shoehorned in like some aftermarket big-block builds of the era.

Inside the Cockpit, the Differences Multiply

The visual cues don’t stop at the fiberglass nose. A genuine GT500 left Shelby American with a wood-rim steering wheel, a toggle-switch panel for the fog lights, and an added oil pressure and amp gauge pod mounted low on the console, details a stock 390 GT fastback never carried from the factory. Those interior pieces are cheaper to fake than the drivetrain, which is exactly why serious buyers cross-reference the console gauges against the VIN and door tag rather than trusting any single detail in isolation.

Why Clones Are So Common on This Body Style

Because the fiberglass hood, nose panel, and taillight surround were sold as reproduction parts for decades, building a convincing GT500 clone out of a 390 GT donor car became a well-worn path for restorers chasing Shelby money without Shelby provenance. Some of these clones are built honestly and sold as tributes, but plenty more have been passed off as the real thing to buyers who didn’t know to check the data plate. Even genuine Shelby American build sheets have been forged over the decades, which is exactly why the most careful buyers insist on physically inspecting stamped VIN locations rather than trusting paperwork alone.

The Production Numbers Behind the Premium

Shelby only built a little over two thousand GT500s for the 1967 model year, a fraction of the roughly 472,000 Mustangs Ford sold that same year across every trim and body style. That kind of scarcity, stacked on top of the 428’s genuine performance advantage over a 390 GT, is exactly why authenticated GT500s routinely sell for multiples of what a comparable big-block 390 fastback brings at auction, even when the two cars look nearly identical from ten feet away. Auction results over the past decade have only widened that gap further, as documented GT500s increasingly draw bidders who specifically collect Shelby cars rather than muscle cars in general.

Restoring One Without Losing the Details

Anyone restoring a 1967 GT500, or a well-documented 390 GT for that matter, runs into the same challenge: sourcing correct reproduction fiberglass and trim that actually matches factory tolerances instead of generic aftermarket panels. Poorly fitted repro noses are a common giveaway on cars that have been through a rough restoration, and matching the factory Holley carburetor calibration on a 428 Police Interceptor takes a specialist who knows the difference between a stock tune and a warmed-over highway-patrol spec engine.

What This Means for Buyers Today

For someone shopping this exact era of Mustang, the smartest move is deciding upfront whether provenance or price matters more, because a beautifully restored 390 GT tribute can deliver nearly identical looks and sound for a fraction of what a documented GT500 commands at auction. Either way, walking away with a correctly sorted 1967 big-block fastback, GT500 or not, means owning one of the most significant chapters in Mustang history.

A Big-Block Fastback Either Way

Whether this particular car turns out to be a documented GT500 or an honest 390 GT, both represent a specific moment when Ford let its pony car grow into something genuinely intimidating on the street. The 1967 redesign gave both engines the room they needed, and decades later, either one parked at a cruise night draws the kind of crowd that a base six-cylinder Mustang never will.

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