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How much horsepower does a 1971 Dodge Demon 340 have?

The 1971 Dodge Demon 340 produced 275 horsepower from its 340-cubic-inch V8 when measured using the era’s gross horsepower standard. This figure is the most commonly cited power number for the Demon 340, though SAE net ratings used later would show a noticeably lower output depending on equipment and testing conditions.


Engine specifications


Below are the core specifications that define the Demon’s powertrain and help explain where the horsepower figure comes from.



  • Displacement: 340 cubic inches (5.6 liters)

  • Engine family: Mopar small-block V8

  • Induction: 4-barrel carburetor

  • Power output: 275 horsepower (gross)

  • Torque (typical range): around 380 lb-ft

  • Drivetrain options: 3-speed manual or 3-speed automatic (TorqueFlite)


These specifications reflect the configuration used in the 1971 Demon 340 and how it earned its reputation as one of the era’s stronger small-block choices.


Horsepower figures and rating standards


The horsepower number for classic muscle cars can be confusing because of historical rating methods. The Demon 340’s most often-cited figure comes from the older gross rating system, which measured engine output with little or no parasitic draw from ancillary systems. Modern discussions frequently reference net ratings, which account for accessory loads and exhaust, and these numbers are typically lower.



  • 275 hp gross (SAE gross, as featured in 1971-era materials)

  • Estimated SAE net horsepower for the period: generally in the low 200s hp, varying by configuration and emissions equipment

  • Modern references often cite the gross figure as the official power number for collectors and enthusiasts


In practice, the Demon 340’s 275 hp gross rating remains the standard figure used by historians and collectors to describe its performance potential in its original form, while net ratings provide a different perspective on the engine’s real-world output during emissions-controlled years.


Summary


The 1971 Dodge Demon 340’s official power figure is 275 horsepower from its 340-cubic-inch V8 under the era’s gross rating. While net horsepower numbers were lower in period tests and vary by configuration, the 275 hp gross rating is the figure most often cited when discussing the Demon’s performance and place in Mopar history.

How much is a 1971 Dodge Demon worth today?


The value of a 1971 Dodge Demon varies significantly by condition, from a low retail price of approximately $8,000 for a fair example to a high retail of about $30,900 for a mint-condition car. Rare or exceptionally well-maintained models with desirable features, such as the 340 V8 engine, can sell for even more, with a recent high-end auction price of $53,000.
 
1971 Dodge Demon value by condition

  • Fair: Around $8,600
  • Good: Around $12,000
  • Excellent: Around $14,900
  • Concours (best): Around $19,000 

Factors influencing value
  • Condition: A vehicle's overall condition is the most significant factor, with excellent, original examples commanding higher prices. 
  • Engine and Options: The 340 V8 engine is a highly desirable and valuable option, and factory-correct or rare options can increase value. 
  • History: Well-documented maintenance history and a lack of accident history or title problems will increase the car's value. 
  • Modifications: While some modifications can add value, extensive or undesirable changes can lower the price, especially for an otherwise original car. 
  • Market Demand: Factors like auction results and recent sales activity can also influence a car's perceived value. 



How much is a 1972 Dodge Demon 340 worth?


The value of a 1972 Dodge Demon 340 varies significantly based on its condition, but in good condition, expect a value of around $32,200, according to Hagerty. Prices can range from approximately $15,750 for a car needing significant work to over $126,500 for a rare or exceptionally well-maintained example with desirable features.
 
Factors influencing value

  • Condition: The car's overall condition is the most significant factor. 
  • Originality: Highly original examples that haven't been heavily modified command higher prices. 
  • Mileage: Low mileage, especially on well-preserved cars, increases value. 
  • History: A clean history with documented maintenance is more valuable. 
  • Modifications: Desirable or high-quality modifications can add value, while poor or excessive modifications can decrease it. 

Price range examples
  • Low end: Around $15,750, typically for cars with extensive maintenance needs or past issues.
  • Average: Around $32,200 for a good condition vehicle.
  • High end: Can exceed $126,500 for pristine, rare, or exceptionally high-quality examples sold at auction. 

Market trends
  • The 1972 Demon 340 was built as an affordable muscle car, and many were driven hard, so finding one in excellent original condition is rare. 
  • The highest prices are reserved for vehicles in top-tier condition with a desirable history and features. 



How much horsepower does a 1971 Duster 340 have?


History

EnginePower SAE netYears
318 V8155 hp (116 kW)1970 - 1971
340 V8235 hp (175 kW)1970 - 1971
240 hp (180 kW)1972 - 1973
360 V8190 hp (140 kW)1975



How many 1971 Dodge Demon 340 were made?


There were 79,959 Demons built in '71, but only 10,098 had the top option, 340ci V-8. In '72, production was down to just 48,500 Demons and only 8,700 340 coupes, so that's clearly the money car for collectors.


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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.