The very word conjures images of Mopar muscle cars in eye-popping “High Impact” colors, smoky burnouts, and stoplight drag races.
An abbreviation of the word “hemispheric,” which describes the domed-shaped combustion chambers that it employs to generate prodigious horsepower and torque, the Hemi has been produced on and off, in various configurations, from the 1950s right up to today.
The most classic iteration – the massive 426 Hemi “Elephant Motor” that saw duty during the Golden Era of muscle in the 1960s and ‘70s – appeared in such legendary muscle cars as the Plymouth ‘Cuda and Superbird, as well as the Dodge Challenger and Charger Daytona.
Typically, 426 Hemi-equipped cars were built in exceedingly small numbers, as the option could inflate the price of a car by nearly half. Many buyers desirous of brute power would often be turned off by the cost and opt for less expensive big blocks such as the 440 or 383 Magnums instead.
One Dodge model released in 1966 was amongst the rarest Mopars ever produced for this very reason, and indeed so few were ordered that only a handful of examples left the factory. The car was a prime example of sleeper understatement as well, and as such, is a favorite of today’s Pentastar faithful.
In this installment of Rare Rides, we’re going to have a look at this snarling street beast – the 1966 Dodge Coronet 500 Hemi convertible!
The model line that led to the ’66 Coronet had its genesis in the post-World War II auto-manufacturing boom, and had two distinct production periods separated by a six-year hiatus.
The Coronet, whose name translates from French to “little crown,” was first introduced in 1949 as a full-sized vehicle with two lesser trim models, the Wayfarer and Meadowbrook, beneath it in the lineup.
Available as a two-door club coupe and convertible, a four-door sedan, and a four-door station wagon, the cars all sported conservative designs that featured pontoon fenders and a fair amount of chrome.
After a slate of refreshes and no less than three total redesigns, Dodge retired the Coronet name in 1959, despite robust sales. It was supplanted by a slew of models, including the Dart Seneca, Dart Pioneer, Dart Phoenix, Matador, and Polara.
This was far from the end of the Little Crown though. The interruption in the Coronet lineage was lifted with the release of an all-new Coronet for 1965. This fifth-generation car was a mid-sized, mid-level offering built on the Chrysler B-body platform.
Styling was svelte, with key design facets transcending all configurations and lines, which now included a base Coronet, Coronet Deluxe, Coronet 440, and the top-of-the-line Coronet 500.
Said styling cues included a full-width “electric shaver” grille encompassing quad lamps underlined with a thick, wraparound chrome bumper, a long, flat hood, a deep relief at the top of the car’s flanks, an upright greenhouse with thin A- and B-pillars, angular C-pillars, a lengthy trunk, and twin, vertical taillights.
While previous generations of the Coronet were armed with a pack of straight-six and small to medium-displacement V8s, Dodge stepped up their game for ’65, designing the car to accept high-performance, big-block engines as well.
Coronet 440 station wagons and all Coronet 500s came with a 273 cubic-inch V8 with 180 horsepower as standard, while all other models got the 225 cubic-inch, 145 horsepower, slant-six.
Available options included a 235-horse, four-barrel version of the 273 V8, a 230 horsepower 318 V8, a 361 cubic-inch lump with 265 ponies, and two big dogs – the classic 383 offering 315 or 330 horsepower, and the monster 426 Max Wedge that could burn the asphalt with 365 horsepower and an astonishing 470 lb-ft of torque.
Transmissions consisted of a standard three-speed manual, an optional A883 four-speed manual, or a TorqueFlite slushbox. The automatic came with a column shifter except on the Coronet 500, which had the shift lever mounted in a center console.
Shockingly, despite extremely healthy sales which topped 200,000 cars for 1965, Dodge decided to completely redesign the Coronet for 1966.
Still riding on the B-body platform, exterior styling was completely new, and decidedly more aggressive looking, incorporating the “Jet-Age” look that was all the rage at the time.
Starting at the front, lower-range models were given a vertical center bar to break the grille up into two halves, while the Coronet 500 featured a crosshair motif. Quad lamps were inset into the grille. The car’s flanks were treated to a unique, concave contouring which was especially attractive and led to a pinch followed by a flare in the bodywork aft of the B-pillar region. Coronet 500s had four horizontal chrome inlays located inside the pinch and flare area.
The rear wheel arches were half-height, covering the upper portion of the rear wheels and tires for a planted stance. The greenhouse was largely the same as ’65, tall and airy, while the still-lengthy trunk led to a rear that now featured twin, horizontally oriented, trapezoidal-shaped taillights.
The new car’s interior was period stylish in appearance as well. A linear, straight-across dash dominated the fore quarters of the cabin with a horizontal cluster containing a complement of rectangular gauges. A large-diameter, thin-rimmed steering wheel with a metal horn ring that was classic Jet-Age in its styling sat in front of it.
All models came with a vinyl interior and chrome trim package. While bench seats were standard on lower trims, plush buckets with quilting that matched the door panels, along with an attractive corrugated chrome-topped center console and a padded dash were stock on the Coronet 500 models.
Besides the redesign, there was big news under the hood too.
While the 225 slant-six, and 273, 318, 361, and 383 cubic-inch V8s remained in the engine roster, Dodge saw fit to replace the 426 Max Wedge with its brand new, immensely powerful lump – the 426 cubic-inch Street Hemi.
Derived from the all-conquering 426 Race Hemi which was so dominant in NASCAR racing that the series threatened to ban it outright unless it was homologated for street use, the Street Hemi was made available in any Coronet aside from the station wagon, regardless of layout or trim level.
Featuring a 4.25-inch bore and a 3.75-inch stroke with a solid-lifter valvetrain, the Hemi touted a 10.25:1 compression ratio, down from the race version’s 12.5:1.
A pair of Carter AFB carburetors were mounted atop a dual-plane, aluminum intake manifold. Spark from the dual-point distributor was delivered to the centrally located plugs in the hemispherical combustion chambers.
2.25-inch intake and 1.94-inch exhaust valves permitted larger ports requiring dual rocker shafts that employed forged-steel rocker arms. A 276-degree duration solid-lifter cam managed the valvetrain. A forged-steel crankshaft and rods were utilized, as were forged-aluminum pistons. Iron exhaust headers sent gasses to dual exhausts that featured a crossover pipe.
Output for the Hemi engine was factory underrated at 425 horsepower and 490 lb-ft of twist – a mammoth amount of go, especially for 1966. In actuality, most Hemis left the factory pushing close to 500 horses.
Transmissions set for Hemi duty were treated to internal strengthening, with the A833 four-speed also receiving a heavy-duty 11-inch clutch, and the TorqueFlite using a higher stall speed torque converter. Likewise, the driveshaft was a beefed-up unit, chosen for “minimum runout and close balance.”
Automatic Hemi cars came equipped with an 8.75-inch rear end housing 3.23:1 gears with a Sure-Grip LSD optional. Four-speed cars came with the massive 9.75-inch Dana 60 with 3.54:1 gears and the Sure Grip standard. Optional ratios were available from Dodge dealers.
The standard Coronet suspension, consisting of unequal-length control arms with torsion bars and tubular shock absorbers up front, and a solid axle on leaf springs with tubular shocks in the rear, was deemed inadequate for Hemi cars. A heavy-duty version of the K-member with a skid plate was thusly installed, as were more robust torsion bars and rear springs. A hefty antisway bar was added to the front, and additional lower body reinforcements were also introduced.
Hydraulically assisted, 11-inch drum brakes and 14 x 5.5-inch steelies with 7.75 x 14 Blue Streak tires rounded up the Hemi Coronet equipment.
Performance of the Hemi car was outstanding for the time, with a period magazine testing a Coronet 500 hardtop at 5.4 seconds zero-to-sixty, and 13.5 seconds at 104 mph through the quarter mile.
Owing to its fine looks, and its excellent performance if optioned properly, the 1966 Coronet was a massive success, outselling the ’65 model with 250,842 cars of all configurations and trims manufactured.
Of that vast number, only 732 Coronets left the factory packing the Street Hemi. 34 Hemis were installed in the base Coronet two-door sedan, 49 into the Coronet Deluxe two-door sedan, 288 into Coronet 440 two-door hardtops, and 340 into Coronet 500 two-door hardtops.
But the rarest of the rare was the Hemi convertible, of which just twenty-one, yes twenty-one, were top-of-the-line Dodge Coronet 500s.
This exceedingly small figure was in no doubt due to the added $320.00 cost of the power convertible top in addition to the $907.60 Hemi engine option, much like what would occur four years later when a smattering of pricey Plymouth Hemi Cuda convertibles and Dodge Hemi Challenger convertibles would be produced.
It is not known how many 1966 Dodge Coronet 500 Hemi convertibles have survived, and sadly the number is probably quite low, given the infrequency that they come up for sale.
When they do hit an auction block, large sums are usually required to procure one, with the blue convertible pictured here selling for $120,000 at the Mecum Indianapolis auction in 2021.
Not too exorbitant a price though for one of Mopar’s great Rare Rides.