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Did Plymouth ever make a 440 Duster?

The short answer is no—Plymouth did not offer a factory Duster with a 440 cubic‑inch engine. The Duster lineup was typically powered by smaller big‑block options such as the 383 and various small blocks, and there is no official record of a factory 440 Duster.

To understand the question, it helps to know that the Plymouth Duster was a compact pony car produced mainly in the 1970–1976 era. It shared its underpinnings with other Mopar models from the same family and was marketed as an affordable performance option in the Plymouth lineup. Engine choices varied over the years, but a factory 440 was not one of them. Some fans and collectors reference rare, non‑factory or one‑off builds when discussing big‑block power in Dusters, but these are not part of Plymouth’s standard production catalog.

Standard Duster engine options

Before listing the engines, note that the Duster offered a range of powerplants, but a factory 440 was not among them. The following options are representative of what you could find in production Dusters.

Slant‑six engine (198 cu in) for base models

318 cubic inch small‑block V8

340 cubic inch small‑block V8

383 cubic inch big‑block V8

These were the typical factory powerplants available through the Duster’s production run, with the 383 being the most potent big‑block option commonly associated with the model. The 440 cubic inches was not offered as a factory Duster engine in Chrysler’s official catalogs.

Rare, non‑factory examples and misperceptions

While there is interest in high‑power Dusters, documented factory records do not show a Plymouth Duster equipped with a 440 engine. There are occasional reports of one‑offs, dealer conversions, or drag‑race‑oriented projects that used larger Mopar engines such as 426 Hemi or 440, but these were not part of Plymouth’s standard production program. Such vehicles are considered rare curios or collector specials rather than factory models.

Notes on historical context

During the 1970–1976 window, Chrysler and its brands offered several performance‑oriented cars, including models that did carry big blocks (like the Barracuda/Challenger line with 426 Hemi or 440 engines). However, Plymouth did not attach a 440 to the Duster in mass production. The Duster remains best known for its 340‑ and 383‑powered variants, as well as its efficiency and handling rather than large‑block power at the factory level.

Collectors should be aware of the distinction between factory production data and aftermarket or one‑off builds. For those seeking verification, consulting original Plymouth brochures, dealership catalogs, and Chrysler corporate records from the era provides the most definitive confirmation that a factory 440 Duster never existed.

Summary

In short, Plymouth did not produce a factory 440 Duster. The Duster lineup offered engine options such as the slant‑six, 318, 340, and 383, but not a 440 from the factory. Rare non‑factory conversions or drag‑tested projects occasionally appear in collector circles, yet they do not constitute a standard production model. As a result, a true factory 440 Duster remains a misconception rather than a documented reality.

For readers curious about this topic, the enduring takeaway is that the Duster’s most powerful factory configurations centered on the 383 and 340 engines, not the 440, and any 440‑powered Duster you might encounter would be a non‑factory build or a customized project rather than an official Chrysler offering.

Was the 440 faster than the 426 Hemi?

The **440 Six-Pack was often faster in stock form, particularly in the quarter mile, but the 426 Hemi had a higher potential for power when modified. Stock 440 Six-Packs generally had better out-of-the-box performance due to how they were tuned and how they hooked up from the line, while the Hemi was a detuned race engine that could be built to produce significantly more power than the 440 with modifications.
You can watch this video to learn about the history and impact of the 426 Hemi: 1mIts Just Cars!YouTube · Jul 31, 2025

Feature	440 Six-Pack	426 Hemi
Stock Performance	Often faster in stock form (e.g., quarter-mile drag racing).	Slower in stock form compared to the 440 Six-Pack.
Power Potential	Lower power potential than the 426 Hemi when both are modified.	Higher power potential when modified, especially with race-spec builds.
Factory Advantage	Lower factory-rated horsepower but with better street-tuned performance.	Higher factory-rated horsepower but often struggled with traction in stock form.
Engine Design	Wedge head engine.	Hemispherical head engine with larger ports and valves.

How much horsepower does a 1970 GTX 440 have?

It's factory equipped with the 440/6 engine. Plymouth called their version of this potent mill the “440 Six Barrel” and “440+6”, while Dodge called it the “440 Six Pack.” Either way, it was rated at 390 horsepower at 4,700 rpm.

What engines were available in the 1970 Plymouth Duster?

The 1970 Plymouth Duster offered a range of engine options, from economical inline-six engines to powerful V8s, including the high-performance 340 cubic-inch V8. The available engines were the 198-cubic-inch and 225-cubic-inch "Slant Six" engines, the 318-cubic-inch V8, and the 340-cubic-inch V8. The 340-powered Duster 340 model was the performance-oriented version of the car.

You can watch this video to learn about the fastest muscle cars in the 1970s: 43sAmerican LegendsYouTube · May 26, 2025

Slant Six: The base models featured economical inline-six engines, specifically the 198-cubic-inch and 225-cubic-inch options.
318 V8: A 318-cubic-inch V8 with two-barrel carburetion was also available for standard Dusters, producing 230 horsepower.
340 V8: The performance-focused Duster 340 came with a 340-cubic-inch V8 that was factory rated at 275 horsepower. This engine was known for strong acceleration and was a budget-friendly muscle car option.

What engine came in a Plymouth Duster?

Plymouth Duster
Engine	198 cu in (3.2 L) Slant 6 I6 225 cu in (3.7 L) Slant 6 I6 318 cu in (5.2 L) LA V8 340 cu in (5.6 L) LA V8 360 cu in (5.9 L) LA V8
Transmission	3-speed manual 4-speed manual 3-speed TorqueFlite automatic
Dimensions
Wheelbase	108.0 in (2,743 mm)

Kevin Bennett

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Kevin Bennet is the founder and owner of Kevin's Autos, a leading automotive service provider in Australia. With a deep commitment to customer satisfaction and years of industry expertise, Kevin uses his blog to answer the most common questions posed by his customers. From maintenance tips to troubleshooting advice, Kevin's articles are designed to empower drivers with the knowledge they need to keep their vehicles running smoothly and safely.