How much horsepower does a 400 Dodge engine have?

The horsepower of a Dodge 400 engine varies widely by year, model, and configuration. In general, you’re looking at a broad range—from roughly 180 horsepower in later, emissions-smoothed versions to about 260–300+ horsepower in early-1970s performance setups, with occasional gross ratings exceeding 300 hp in high-performance variants.

The Dodge 400 refers to a 400 cubic inch V8 used by Chrysler/Mopar in the 1970s and related years. Because Chrysler, like other manufacturers of the era, switched between gross and net horsepower ratings and because emissions controls changed the engines’ output over time, there isn’t a single fixed figure. The exact horsepower depends largely on the engine’s carburetion, compression, cam, exhaust, and the regulatory environment of the model year.

What is the Dodge 400 engine?

The Dodge 400 is a members of Mopar’s large-block family and was deployed in various Dodge and Plymouth models throughout the 1970s. It displaced 400 cubic inches (approximately 6.6 liters) and came in multiple configurations, including two-barrel and four-barrel carburetors, different compression ratios, and various exhaust setups. Because horsepower ratings shifted with emissions regulations and testing standards, the same basic engine could show notably different numbers depending on the source and the year.

Horsepower by configuration

Before listing the typical ranges, note that horsepower statements depend on the carburetor, compression ratio, exhaust, and emissions settings. The following ranges are representative of stock factory setups across the 1970s.

• Two-barrel carbureted 400: roughly 180–210 horsepower (net ratings, emission-era, street applications).


• Four-barrel carbureted 400 (standard performance): roughly 230–260 horsepower (net).


• Four-barrel carbureted 400 with performance cam and exhaust (early 1970s high-performance packages): roughly 260–300+ horsepower (gross; net commonly around 230–260).


• Late-1970s smog-era 400 (often 2-barrel or 4-barrel with stricter emissions): roughly 180–230 horsepower (net).

These ranges illustrate that the engine’s horsepower was not fixed; it depended on the configuration and the era’s regulatory environment. For precise figures, consult the specific vehicle’s build sheet, owner’s manual, or factory documentation for that model-year.

Net vs. gross horsepower and emissions effects

Two important caveats help interpret these numbers. Gross horsepower numbers (older, pre-emissions testing) can be significantly higher than net numbers (the way most post-1970s ratings are published), because net horsepower accounts for accessories and exhaust losses. Emissions controls added in the 1970s also typically reduced the engine’s effective output. When comparing figures, always note whether the source uses gross or net ratings and the model year’s regulatory context.

How to identify the horsepower for a specific Dodge 400

To determine the exact horsepower for a particular engine, you should reference the car’s original documentation and inspect its configuration. Look for the engine code, build sheet, or fender tag, and cross-check with Mopar catalogs or factory literature for that year. If you’re restoring, knowing whether the engine is a stock two-barrel or four-barrel setup, along with compression ratio and exhaust, will help you estimate where it sits within the typical ranges above. Aftermarket changes can also alter actual power output, so measurements from a dynamometer (dyno) can be the most precise method for a given engine in a given state of tune.

Summary

The Dodge 400’s horsepower is not a single, fixed figure. Across its lifespan, the engine ranged from roughly 180 to 260 horsepower in common street configurations, with certain early-1970s performance versions climbing toward 300 horsepower or more on gross ratings. Emissions controls and the switch from gross to net horsepower testing further shaped the numbers. For anyone assessing a specific 400, the best approach is to verify the exact year, carburetion, compression, exhaust, and the official documentation for that vehicle, rather than relying on a generic figure.

How much horsepower does a 1977 Dodge 400 have?

1977 Dodge Royal Monaco Brougham V-8 400 c.i. 190 h.p. automatic 3 speed.

Why is a 383 better than a 400?

Through completely different engineering approaches. The 383 stroker delivered its power through aggressive bore. And stroke combinations that maximized breathing efficiency.

Did Dodge make a 400 engine?

Yes, Dodge (as part of Chrysler) did make a 400 cubic inch engine, which was part of the B-series engine family. This engine was introduced in 1972 and was available in a variety of vehicles, including cars, trucks, and motorhomes. 

• Introduction: The 400 engine was developed by increasing the bore size of the 383 engine. 
• Specifications: It was the largest-bore production V8 engine made by Chrysler at the time of its introduction. 
• Availability: The 400 was used in a wide range of applications throughout the 1970s and was available in different power levels depending on the vehicle and configuration. 
• Legacy: The Mopar 400 big-block engine is still popular in the performance and racing community today. 

How much horsepower does a 400 big block have?

A stock Chrysler or Ford 400 big block engine typically produces 160–260 horsepower, but performance builds can achieve 400+ horsepower, with some custom builds reaching over 500 or even 700 horsepower. Stock horsepower varies by year and application (e.g., car, truck, or motorhome) and declined due to emissions controls over time.
 
Stock horsepower ratings

• Chrysler 400: Factory ratings ranged from 170 hp for the two-barrel version to 260 hp for the high-performance four-barrel/dual-exhaust model. 
• Ford 400M: Produced between 160 and 180 horsepower in stock trim, according to Facebook users. 
• Chevrolet 409: While not a 400 cubic inch engine, this similar engine is often mentioned. In 1963, a high-performance version produced 425 hp. 

High-performance builds

• Custom builds: By using aftermarket parts, high-performance builds can achieve significantly more horsepower. 
• 400+ hp: It is common to build a 400ci engine to exceed 400 horsepower with a combination of updated components. 
• 500+ hp: Builds are available that target and achieve 500 hp or more. 
• 700+ hp: Extreme applications, such as pulling trucks, can reach well over 700 horsepower. 

This video shows how to build a 400 hp Mopar engine: 54sJustMoparJoeYouTube · Jun 1, 2022