Dodge Challenger and HEMI Dart – LOUD Mopars!

A 1970 Dodge Challenger and a 1968 Hemi Dart share an engine family and almost nothing else. One was Dodge’s upmarket answer to the pony car wars, sold at dealerships nationwide with everything from a slant six to a 426 Hemi. The other was built off-site by Hurst because Chrysler refused to sanction it, in a run of just 80 cars. Read on for how both came to exist, and why they sound nothing alike.

Park a 1970 Dodge Challenger next to a 1968 Hemi Dart and the family resemblance stops at the badge. One was Dodge’s considered answer to a pony car market it had arrived at late, engineered to be sold at every dealership in the country to buyers who wanted a comfortable car with an intimidating engine option. The other was barely a road car at all, built in a number so small it would fit in a single parking row, assembled by an outside contractor because Chrysler itself declined to put its name on the operation. They share an engine family and almost nothing else, and the reason why is one of the strangest stories in Mopar history.

The Car Chrysler Refused to Build

When Dodge wanted to put the 426 Hemi into the compact A-body Dart for Super Stock competition, Chrysler’s own management declined to authorize a factory installation. The engine was enormous, the car was small, and the resulting vehicle would have been effectively impossible to warrant or insure as a normal passenger car. Dodge went around the problem by contracting Hurst Performance to carry out the conversion off-site, producing the cars under the LO23 order code. It is one of the few instances in American automotive history where a manufacturer’s answer to internal resistance was to outsource the entire program to a shifter company.

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Eighty Cars, Built to Be Ruined

Just 80 Hemi Darts were produced, alongside a similarly tiny run of Hemi Barracudas built under the parallel BO29 code. These were not detuned street cars. The build specification deleted the rear seat, carpeting, radio, heater, sound deadening, and armrests, substituted lightweight A100 van seats, fitted a fiberglass hood with a functional scoop along with fiberglass front fenders, and used acid-dipped sheet metal to shed still more weight. Side glass was replaced with lightweight material. The finished cars weighed somewhere in the region of 3,000 pounds and were delivered in primer, since the buyer was expected to paint and letter the car for competition anyway.

What 425 Horsepower Really Meant

The factory rating was 425 horsepower, a figure that was almost certainly a substantial understatement. Contemporary and modern estimates for the 426 Hemi in this configuration, with its dual four-barrel carburetors on a cross-ram intake, hemispherical combustion chambers, and solid lifter valvetrain, commonly land several hundred horsepower higher than the published number. Chrysler had every incentive to publish a conservative figure, both for classification purposes in Super Stock competition and because a truthful number would have made the car uninsurable. These cars were capable of running the quarter mile in the low ten second range essentially as delivered, with sub-ten-second passes well within reach once a competent racer had set one up.

The Challenger Arrives Late and Arrives Loaded

The Challenger arrived two years later and represented the opposite philosophy entirely. Dodge came to the pony car segment years after Ford and Chevrolet had established it, and it compensated by building something larger and more comfortable than either. The E-body Challenger shared much with the Plymouth Barracuda but rode on a longer wheelbase and offered more interior room. It was positioned as the upmarket entry, with a broad options list, better trim materials, and the explicit intention of competing with the Mercury Cougar as much as with the Mustang. Dodge built roughly 77,000 Challengers in that first 1970 model year across all body styles and trim levels.

An Order Sheet That Ran From Sensible to Absurd

The engine range was extraordinary in its breadth. A base Challenger could be ordered with a 225 cubic inch slant six, which is a genuinely modest engine, while the R/T could be specified with the 383 Magnum rated at 335 horsepower, the 440 Magnum at 375, the 440 Six Pack with its trio of two-barrel carburetors at 390, or the 426 Hemi at the familiar 425. The same body could therefore be configured as an economical commuter or as one of the most formidable street cars of the era, which is precisely how Dodge intended it. Hemi Challengers were produced in very small numbers relative to the total, which is why they now occupy the top of the market.

The T/A and Its Own Homologation Problem

The Challenger also had its own homologation story. Dodge built the T/A variant specifically to qualify for SCCA Trans-Am racing, which required a production run of street cars. The T/A used a 340 cubic inch small-block topped with three two-barrel carburetors, a fiberglass hood with an integrated scoop, side-exit exhaust, and staggered tire sizes front to rear. Around 2,400 were built for the 1970 model year alone. The racing effort itself was short-lived, and the T/A did not return for 1971, which leaves it as a single-year car built for a purpose Dodge abandoned almost immediately.

Why These Two Sound So Different

The acoustic difference between these two cars is not subtle, and it comes down to how each was built. The Hemi Dart has essentially no sound deadening, a fiberglass hood that transmits rather than absorbs, and an exhaust system designed for competition rather than for a neighborhood. Its solid lifter valvetrain contributes a mechanical clatter that a hydraulic setup simply does not produce. The Challenger, even in R/T form with a big-block, was built as a road car with insulation, carpet, and a full interior, so its exhaust note reaches the cabin filtered rather than raw. Both are loud. Only one of them was designed to be tolerable on a two-hour drive.

Survival Rates and What They Did to Values

Attrition has shaped the values of both cars in different ways. The Hemi Darts were built expressly to be raced, and a meaningful portion of the 80 were crashed, cut up, re-bodied, or simply consumed in competition over the following decades. The survivors, particularly those with documented history, are now among the most valuable Mopars in existence. Challengers were built in far greater numbers and survived in far greater numbers, but the Hemi and Six Pack cars have followed a similar trajectory, with documentation and matching numbers driving an enormous spread between a well-optioned R/T and an ordinary example.

Two Cars, One Engine Family, Two Verdicts

Set side by side, the two cars make a useful point about what the muscle car era actually was. It was not a single coherent movement but a collision between marketing departments building attractive, profitable road cars and engineering departments quietly building competition equipment that happened to be street-legal on a technicality. The Challenger is the former executed at a very high level. The Hemi Dart is the latter, unapologetically. That both wore Dodge badges in the same three-year window says more about the period than any horsepower figure does.

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