Ford Mustang 1967 S-Code GT Fastback

Ford put one engine at the very bottom of the 1967 Mustang order sheet that almost nobody circled: the S-Code 390, a 320-horsepower FE big block that required a redesigned engine bay just to fit. Buyers looked at it, looked at the lighter small-block GT beside it, and mostly walked away. That indifference is exactly why a documented S-Code GT fastback in original spec is now one of the harder first-generation Mustangs to verify and to find.

Ford’s 1967 Mustang order sheet had a code near the bottom of the engine list that almost nobody circled. It cost real money, it dropped roughly 150 additional pounds directly over the front wheels, and it required Ford to redesign the engine bay just to make it fit, because the Mustang had spent its first three model years with no room for anything that large. Buyers looked at it, looked at the lighter small-block GT parked next to it on the lot, and walked away in overwhelming numbers. That indifference is precisely why a documented S-Code GT fastback in original specification is now one of the harder first-generation Mustangs to find and verify.

The Restyle That Made Room for an FE

The 1967 Mustang was the first significant restyle of the original car. Ford widened the track, widened the body by roughly two inches, deepened the sculpting along the flanks, and enlarged the engine compartment specifically so the FE-series big block would clear the shock towers. The fastback roofline changed too, running in an unbroken line to the tail rather than terminating in the earlier car’s shorter deck. All of it added weight, which annoyed purists then and still does now, but without those changes the 390 simply could not have been offered, and the 428 that followed a year later would have had nowhere to go.

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What the S-Code Actually Bought You

The S-Code designation meant a 390-cubic-inch FE V8 with a four-barrel carburetor, rated at 320 horsepower at 4,800 rpm and 427 lb-ft at 3,200 rpm, on 10.5-to-one compression. Cars ordered with it also received a specific 390 performance air cleaner assembly and a heavier-duty radiator to cope with the extra heat and mass ahead of the front axle. Those are gross ratings, as everything was in 1967. What the numbers do not convey is the delivery: the FE was a torque engine first, pulling hard from just off idle and running out of enthusiasm well before the tachometer got interesting.

The GT Package Was a Separate Box to Tick

The GT equipment group was ordered separately from the engine and could be combined with several V8s. It brought fog lamps mounted in the grille, rocker panel stripes, a dual exhaust system with quad outlets exiting through the rear valance, power front disc brakes, a heavy-duty handling suspension, and specific badging. Cars ordered with the GT package and an automatic transmission were designated GTA. Because the two options were independent, a GT badge alone tells you nothing about what is under the hood, and a 390 alone tells you nothing about the brakes and suspension. The combination is what makes a car interesting.

Why the Small Block Kept Winning the Sale

Most buyers chose the small block, and they were not wrong to. A 289-powered Mustang was cheaper to buy, cheaper to insure, and dramatically better balanced, with noticeably lighter steering and a front end that would actually turn. Period road tests were blunt about the 390 car’s understeer and its appetite for brakes, and in a famous magazine comparison against its rivals the big-block Mustang finished at the back of the field. Ford was chasing a specification-sheet number rather than a driving experience, and the buying public, given both cars side by side in the same showroom, could feel the difference.

How Few Were Really Built

Ford installed roughly 28,800 390 four-barrel engines across 1967 Mustang production, which sounds like a substantial number until you consider the context. Total 1967 Mustang output was about 472,121 cars, of which the 2+2 fastback body style accounted for roughly 71,042. Narrow that to fastbacks that also received the GT equipment group and the S-Code engine together, then narrow again to a specific factory color and option combination, and the survivors of any single configuration number in the dozens rather than the thousands. That intersection, not the raw 390 count, is what makes a car like this scarce.

The Shelby Sitting One Shelf Above

One shelf above sat the Shelby cars, and they complicate the picture. The 1967 GT500 used a 428 Police Interceptor-based engine rated at 355 horsepower, while the GT350 continued with the high-revving 289. That left the S-Code 390 in an awkward middle position: more engine than most buyers wanted, less engine than the badge-conscious buyer with real money would settle for. It is a familiar pattern in the muscle car era, and it usually produces exactly the outcome it produced here, low sales in period followed by genuine rarity and rising interest half a century later.

The Cobra Jet Made It Obsolete Overnight

Ford solved the problem in April 1968 by introducing the 428 Cobra Jet, rated at 335 horsepower in a rating almost universally regarded as deliberate understatement, and capable of mid-thirteen-second quarter miles in stock trim. The 390 did not disappear immediately; it remained on the Mustang order sheet alongside the Cobra Jet through 1969 before finally being dropped. But its role changed overnight from performance flagship to comfortable touring engine, which is why the 1967 and early 1968 S-Code cars occupy such a specific and short-lived window in Mustang history.

How to Document a Real S-Code

Documenting an S-Code starts with the fifth character of the VIN, which must be an S. From there, a Marti Report drawn from Ford’s surviving production records will confirm the original engine, transmission, axle ratio, paint and trim codes, and whether the GT equipment group was actually ordered. The door data plate should agree with all of it. Then verify the engine itself: FE casting numbers and date codes must predate the car’s assembly date by a sensible margin. Re-stamped and swapped FE blocks are common, and on a car this scarce the paperwork is worth more than any single component.

A Transitional Car Worth Understanding

None of this makes the S-Code the best-driving 1967 Mustang, and anyone shopping for a back-road car should test a 289 or 302 first. What it makes it is historically specific: the moment Ford proved a big block would physically fit, before it worked out which big block actually belonged there. That transitional quality, combined with production numbers thin enough to make correct examples genuinely hard to source, is why documented S-Code GT fastbacks keep appearing at the serious end of the auction catalogue rather than the affordable end.

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