1966 Dodge Coronet Hemi

Introduced in 1965, the Coronet would carry much of Dodge’s performance banner through the balance of the decade. A cleanly styled mid-size on a 117-inch wheelbase, its most distinguishing design cue was a rear roof pillar on the sedans and hardtops that was wider at the top than at the bottom. MoPar enthusiasts warmed to the Coronet right away when they noticed the options list included the 365-horsepower 426 street wedge.

1966 Dodge Coronet Hemi
The 1966 Dodge Coronet Hemi was called “one of the fastest
and most fantastic sedans ever.”

For those who searched a little deeper, there was the mighty 426 Hemi V-8 on the list of extra-cost powerplants. “Our new 426 Coronet ought to have its head examined,” one ad for the ’65 Coronet slyly stated. What Dodge didn’t make clear was that this was the race Hemi, with a volatile 12.5:1 compression ratio that made it ill-suited for street use.

That changed in 1966 -- the year of the Street Hemi. Hot Rod magazine called it “one of the fastest and most fantastic sedans ever.”

Unlike the race Hemi that snuck under some 1965 Coronet 500 hoods, this one had a more tolerable 10.25:1 compression, achieved by the use of pistons with lower domes. A milder camshaft was installed and a heat chamber was added to manifolds so the engine would warm up properly. Basically a detuned edition of the earlier race Hemi, this street version carried cast-iron heads and exhaust manifolds -- considerably quieter than the tubular steel headers in race Hemis.

Twin progressive-action Carter AFB four-barrel carburetors sat atop an aluminum dual-plane intake manifold. One carburetor gained a choke, and an inline carburetor configuration replaced the race-oriented ram induction. Otherwise, the two powerplants were similar, built tough to handle a wallop of torque. They looked tough, too, with black-crackle valve covers astride the bright-Hemi-orange block.

Dodge rated the result at 425 horsepower at 5000 rpm and 490 pounds/feet of torque at 4000. Pure stock, it would blast the 3400-pound unibody Coronet to 60 mph in 5.3 seconds and through the quarter in 13.8 seconds at 104 mph. The acceleration, said Motor Trend, was “absolutely shattering.”

Hemi-powered Coronets added an extra leaf to the rear springs. Those equipped with Chrysler’s A-833 four-speed manual gearbox got a Dana rear end with the biggest ring gear on the market at 93/4 inches. A variety of axle combinations was available, but for street/strip use, the TorqueFlite automatic with the 3.54:1 Dana Sure-Grip was a good compromise.

Part of Chrysler’s motivation for bringing the Hemi to the boulevards was to certify it once again for NASCAR racing by building at least 500 streetable examples. The Hemi had dominated NASCAR in 1964 and, deciding it wasn’t sufficiently a production engine, NASCAR banned it for the 1965 stock-car season. (This prompted the unlikely sight of oval-king Richard Petty campaigning a Hemi-powered drag racer in ’65. Fittingly, his Super Stock Barracuda was called “Outlawed.”)

For ’66, the engine was made available at Dodge in the Coronet and in the new fastback Charger, which was basically a rebodied Coronet. Many street racers opted for the less-expensive Coronet, even though the Hemi added nearly $1000 to the most modest Coronet’s $2705 base price.

Still, even with optional bucket seats and console, a Coronet was less flashy than the Charger. And without the scoops and stripes that would become fashionable just a few years down the road, the guy in the next lane wasn’t likely to know what lurked beneath your Coronet’s hood until you were long gone. About the only external clue was a discrete Hemi badge on the front fender.

Any Coronet could be ordered with a Hemi engine, though fewer than 1000 ’66 models had it. That total includes just 27 convertibles, and amazingly, two four-door sedans.

“You know what a Hemi is,” taunted one Hemi Coronet ad. “It’s that wailing stocker that’s about a car length ahead at the end of the quarter....If you insist on playing fair, forget it. But if you have just a trace of mean in your all means, get one.”

Engine Type
Displacement (cid)
Horsepower @ rpm:
425 @ 5000
Torque (pounds/feet) @ rpm
490 @ 4000
Compression Ratio
Bore (inches)
Stroke (inches)
Valve Lifters
Coronet, Charger


0-60 mph (sec)
0-100 mph (sec)
1/4-mile (sec)
13.8 @ 104 mph
Top speed (mph)
Axle ratio

*Source: Car and Driver

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