1967 Chevrolet Impala SS Convertible

A full-size family convertible that runs 15.8 seconds in the quarter-mile shouldn’t exist by most 1960s logic, but Chevrolet built exactly that when it slotted the Z24 Super Sport package onto the Impala for 1967. Hidden under understated styling sat a genuine 427 big-block rated at 385 horsepower, installed in only 2,124 Super Sports that year. Read on to find out how rare a documented convertible like this one actually is.

A full-size family convertible that runs 15.8 seconds in the quarter-mile shouldn’t exist, at least not by the logic most people apply to 1960s Detroit iron. Big, comfortable convertibles were supposed to be for cruising, not embarrassing dedicated muscle cars off the line. Chevrolet built exactly that contradiction anyway, when it slotted the Z24 Super Sport package onto the full-size Impala for 1967 — and the result genuinely humbled buyers who assumed a car this size and this comfortable had no business keeping up with anything wearing a factory stripe. What was actually hiding under that Impala’s hood, and just how few of these were ever built with the real deal?

A Package Built to Hide in Plain Sight

Order the Z24 package on an Impala SS Sport Coupe or Convertible in 1967, and Chevrolet handed you the L36 427, a Turbo-Jet big-block rated at 385 horsepower and 460 lb-ft of torque, wrapped inside sheetmetal most people assumed was purely a comfort-oriented family car. Chevrolet’s full-size lineup that year also included plainer six-cylinder and small-block Impala variants sharing identical exterior sheetmetal, meaning a Z24 car looked nearly indistinguishable from a base model to anyone who didn’t know exactly what to check under the hood.

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Two Ways to Row It

Buyers could pair the L36 with either a three-speed manual transmission or the three-speed Turbo Hydra-Matic automatic, giving the Z24 package genuine flexibility for buyers who wanted serious straight-line performance without committing to a clutch pedal on a car this size. The manual-equipped cars in particular have become especially prized among collectors today, since far fewer buyers opted to row their own gears in a car most people assumed was built purely for comfortable cruising.

The Details That Gave It Away

The package wasn’t subtle once you knew what to look for: a special hood with unique ornamentation, SS 427 badging front and rear, F40 heavy-duty suspension components, dedicated Super Sport wheel covers, upgraded gauges, and Strato-bucket or Strato-back seating with a center armrest all came bundled together. None of those cues were loud by muscle car standards of the era, which is exactly why a Z24 Impala could surprise unsuspecting drivers who judged the car purely by its size and body style rather than its badges.

How Rare Is Genuinely Rare

Chevrolet only installed the 427 into 2,124 Super Sports that year out of 2,141 total Z24 packages built, and nobody’s kept a definitive count of how many of those were convertibles rather than hardtops, which makes a documented ragtop like this one meaningfully scarce even within an already small production run. Comparable big-block intermediate muscle cars from the same model year, like a Chevelle SS 396, sold in far larger numbers, making the Impala’s genuinely low production figures easy to overlook simply because the model wasn’t marketed primarily as a performance car.

Numbers That Held Their Own

A ’67 SS 427 could run 0-60 mph in roughly 8.4 seconds and cover the quarter-mile in 15.8 seconds — figures that hold up against plenty of dedicated intermediate muscle cars from the same model year, all while the Impala was simultaneously hauling a family and a folding top around town. Period road tests specifically noted how unexpected that kind of quarter-mile time felt coming from a car with the Impala’s full-size dimensions and comfort-oriented reputation.

A Full-Size Car With Intermediate-Car Manners

Most of Detroit’s genuine quarter-mile performance in 1967 came from intermediates like the Chevelle SS and GTO, purpose-built lighter platforms specifically engineered around straight-line speed, which makes a full-size Impala keeping pace an unusual engineering achievement rather than an accident of spec sheet math. Chevrolet’s engineers essentially proved a full-size platform could deliver genuine muscle car numbers if given the right combination of engine, gearing, and suspension tuning, a lesson the intermediate-focused muscle car segment largely ignored at the time.

Built for a Buyer Nobody Else Was Chasing

Chevrolet built this combination deliberately for shoppers who wanted a big, comfortable, genuinely practical everyday car that could still embarrass unsuspecting muscle car owners at a stoplight — a different mission entirely from the intermediate muscle cars built purely to win magazine comparison tests. That buyer profile — practical on the surface, genuinely quick underneath — has become increasingly appreciated by modern collectors who value a car’s ability to surprise over one that announces its performance from across a parking lot. That same logic would later influence how enthusiasts evaluated other full-size performance packages across the industry, treating unexpected capability as a selling point rather than a curiosity.

The Convertible Top Made It Rarer Still

Adding a power convertible top to an already limited Z24 package pushed production numbers even lower, since folding-top hardware, reinforced structure, and the added weight made the convertible a harder sell to buyers focused purely on quarter-mile bragging rights. Structural reinforcement alone added measurable weight to convertible-bodied Impalas compared to their hardtop counterparts, a tradeoff serious quarter-mile-focused buyers of the era often avoided in favor of the stiffer, lighter coupe.

Why Documentation Matters So Much Here

With production numbers this small and no dedicated convertible tally ever published, verifying a genuine Z24-package Super Sport convertible today depends heavily on surviving build sheets, cowl tags, and matching-numbers documentation rather than visual inspection alone. Third-party verification services specializing in GM muscle car authentication have become an increasingly common step for buyers considering a six-figure purchase on a car this rare and this easy to misrepresent.

A Sleeper Chevrolet Built on Purpose

Six decades later, that combination of everyday practicality and genuine quarter-mile performance is exactly what makes this generation of Impala SS so collectible — proof Chevrolet’s engineers understood there was a real market for performance wrapped in a car nobody would suspect until the light turned green. It remains one of the clearest examples in Chevrolet’s own history of engineering genuine performance into a package most contemporary buyers never thought to question. Anyone shopping for one today should expect real competition from collectors who understand exactly how special the combination of a big-block, a manual gearbox, and a folding top actually is.

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