This 1968 Hemi Dart Is The Strangest Ever!

Most Hemi Dart stories are about the famous 1968 factory lightweights built for NHRA Super Stock racing around the 426 Race Hemi. This 1968 Dodge Dart GTS tells a different one: a first-generation Chrysler FirePower Hemi, bored from 331 to 342 cubic inches, tucked under a completely stock-looking hood and fenders. It’s an engine most Mopar fans forgot Chrysler ever built into a Hemi lineage at all. Read on to find out how a discontinued 1950s engine ended up hiding inside a 1968 A-body.

Say the words ‘Hemi Dart’ to a Mopar fan and one specific car comes to mind: the ultra-rare 1968 factory lightweight built around the monstrous 426 Race Hemi for NHRA Super Stock competition. This car isn’t that car, and that gap is exactly what makes it worth a second look. Underneath this 1968 Dodge Dart GTS’s stock-looking hood sits a completely different Hemi — one most enthusiasts forgot Chrysler ever built, bored out well past its original displacement and hiding in plain sight where nobody expects to find it. What is this engine, and why does finding one in a Dart feel this strange?

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The Hemi Everyone Forgot Existed

Long before the 426 ‘elephant’ Hemi became a muscle car icon, Chrysler built an entirely different hemispherical-head V8 family under the FirePower name, starting with a 331-cubic-inch, 180-horsepower version introduced for the 1951 model year. That first-generation Hemi grew through 354 and eventually 392 cubic inches by 1958 before Chrysler retired the design in favor of cheaper, lighter wedge-head engines — a full decade before the 426 Hemi most enthusiasts recognize today ever existed. Chrysler built that first-generation Hemi in three displacements across the decade — 331, 354, and 392 cubic inches — each version chasing more compression and more horsepower before the whole family was quietly discontinued.

342 Cubic Inches of a Very Different Story

This build takes that early 331-cubic-inch FirePower block and bores it out to 342 cubic inches, tucked under the Dart’s stock fenders and factory hood rather than the tunnel-ram setups and fiberglass hoods associated with drag-only Hemi Darts. It isn’t chasing the factory L023 lightweight’s straight-line drag credentials; it’s a period-correct-looking street car hiding an engine most Mopar fans associate with 1950s letter cars, not a compact 1968 A-body. The stock-appearing exterior means this car can pass casual inspection at a cruise-in or a stoplight, giving away nothing about the machine work hidden beneath the factory sheet metal.

Why the Real Hemi Dart Is So Rare

The car this one gets mistaken for — the genuine 1968 Hemi Dart — was a purpose-built factory lightweight, assembled in a run of roughly 80 cars specifically for NHRA Super Stock and AWB drag racing, stripped of sound deadening and fitted with fiberglass hoods and doors. Genuine examples now sell for well over six figures at major auctions, which is exactly why a stock-bodied Dart hiding a completely different vintage Hemi under an ordinary hood catches so many people off guard at a glance. Those originals also relied on a period-specific 727 TorqueFlite automatic or a heavy-duty four-speed, drivetrain hardware that has become nearly as hard to source today as the cars themselves.

FirePower’s Decade of Quiet Dominance

Chrysler’s first-generation Hemi wasn’t a novelty engine in its own era — FirePower V8s powered Chrysler’s flagship models throughout the 1950s and built the brand’s early reputation for high-compression, hemispherical-chamber performance long before muscle cars existed as a category. DeSoto and Dodge ran their own variants under different names, but the underlying architecture, and the manufacturing cost that eventually killed it, was shared across the whole family.

Why Chrysler Walked Away From Its Own Hemi

Chrysler retired the first-generation Hemi specifically because it was expensive to build: the hemispherical combustion chamber required larger, heavier cylinder heads and more complex valvetrain geometry than a conventional wedge-head design, all for a horsepower advantage that shrank as wedge-head technology improved through the late 1950s. That cost equation is exactly why the Hemi name disappeared for most of the 1960s before Chrysler revived it in the 426 for 1964. Chrysler’s own engineers reportedly found the hemispherical design added significant cost and weight for a horsepower gain that shrank year over year as wedge-head cylinder heads improved, which is exactly why the corporate accountants eventually won the argument.

A Dart Built to Hide In Plain Sight

Where a genuine drag-package Hemi Dart announces itself with a hood scoop and stripped-out interior, this build goes the opposite direction — factory-style paint, an intact interior, and a hood that gives away nothing about what’s bored out underneath it. That contrast is deliberate: a builder chasing attention would drop in a 426, not resurrect a discontinued engine family most Mopar fans have never seen in person. Builders who take this route usually do it precisely because a first-generation Hemi swap draws knowing nods from serious Mopar historians in a way a common 426 conversion no longer does.

Boring Out History Instead of Buying It

Finding a period-correct 331-derived FirePower block healthy enough to bore to 342 cubic inches and build into a running street engine is its own kind of rare — these blocks haven’t been in regular production for well over six decades, and most surviving examples exist in museums or static collections rather than daily-driven cars. Whoever built this Dart chose the harder, stranger path over simply sourcing a more common 426. Sourcing a period-correct block is only the first hurdle — most surviving first-generation Hemi cores need extensive machine work before they can safely handle a bore job of this size, which adds real cost on top of scarcity.

A Reminder of Chrysler’s Deeper Hemi History

The 426 gets all the attention in muscle car conversations, but engines like this one are the reason Mopar’s hemispherical-head lineage stretches back to 1951 rather than starting with the muscle car era. For collectors who know the full FirePower story, a Dart built around a first-generation Hemi isn’t a curiosity — it’s a direct link to the engine family that made the 426 possible in the first place. Chrysler’s FirePower name lived on for years in advertising even after the hemispherical engines themselves were phased out, a branding echo that outlasted the hardware by nearly a decade.

The Strangeness Is the Whole Point

That mismatch between what this Dart looks like it should have and what’s actually sitting under the hood is exactly why it keeps getting called the strangest Hemi Dart out there. It isn’t chasing a record or a sanctioning body’s rulebook — it’s a reminder that Mopar’s Hemi story has more chapters than the one everybody already knows. Share your thoughts in the comments below. That’s the kind of detail that turns a casual show-goer into someone who lingers at the fender well a little longer than they planned to.

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