How much horsepower does a 440 six pack really have?
In its prime, the 440 Six-Pack carried a bold power claim: about 390 horsepower using the era’s SAE gross rating, with peak torque around the high-400s pound-feet. In today’s terms, if you translate to SAE net ratings and factors like emissions equipment, you’re looking at roughly 300–350 horsepower depending on year, configuration, and tuning.
A quick look at the Six-Pack setup
The 440 Six-Pack refers to a 440 cubic inch V8 equipped with three two-barrel carburetors (a “six-pack”), a high-rise intake, and a relatively aggressive cam. It was offered in Mopar muscle cars such as the Plymouth Barracuda/’Cuda and Dodge Challenger/Charger from about 1969 through 1974. The setup was designed to deliver strong low- to mid-range torque and a high peak power number for its era.
Official numbers by era
Here are the commonly cited factory horsepower figures tied to the era’s rating methods. Note that these reflect the measurement standards then in use and may not align with modern net horsepower tests.
- 1969–1970: SAE gross horsepower around 390 hp; torque commonly listed near 490 lb-ft.
- 1971–1972: SAE net horsepower typically in the low 300s (roughly 320–350 hp), depending on exhaust, compression, and drivetrain losses in the test configuration.
- 1973–1974: SAE net horsepower still in the 300–330 hp range in most configurations, with variations by model and emission controls.
Conclusion: The Six-Pack numbers reflect a transition from gross to net ratings and to stricter emissions rules, which is why the official figures shift over time even for the same engine family.
What this means for enthusiasts today
For a vintage Mopar owner or a dyno organization testing a restored setup, the following factors drive the measured horsepower of a 440 Six-Pack:
- Measurement standard: gross vs net horsepower dramatically changes the number you’ll report.
- Engine condition: compression, cam timing, carb tuning, and intake/exhaust specifications influence power output.
- Emissions equipment: air injection and exhaust components commonly reduce net power in later models.
- Car’s drivetrain and weight: horsepower is only part of the performance picture; torque and gearing matter as well.
Conclusion: The familiar 390 hp figure remains the iconic headline for the 1969–1970 Six-Pack, but actual output on a test stand today under net ratings typically lands in the 300–350 hp range depending on setup.
Summary
The 440 Six-Pack is celebrated for its era-appropriate punch. Its horsepower is best understood as a product of rating method plus year and configuration: roughly 390 hp gross in the early 1970s, about 300–350 hp in net ratings under later standards, and variable with condition and exhaust. For restorations and dyno tests, use net horsepower figures for modern comparison, and expect a range depending on how closely you match the original spec.
What is the difference between a 440 six pack and a 440 magnum?
The main difference is that the 440 Six Pack is a high-performance version of the 440 Magnum, featuring a triple-carburetor setup (three 2-barrel carbs) instead of a single 4-barrel carb. This results in more power (390 HP vs 375 HP for the Magnum) and a higher compression ratio. The Six Pack also includes other specific upgrades like a different camshaft, pistons, and a dual-point distributor, as well as a reinforced oil pan and K-frame skid plate.
440 Magnum
- Fuel delivery: One 4-barrel carburetor.
- Power: Approximately 375 HP.
- Torque: Approximately 480 LB-FT.
- Compression ratio: 9.5:1.
440 Six Pack
- Fuel delivery: Three 2-barrel carburetors (a "six pack" of barrels).
- Power: Approximately 390 HP.
- Torque: Approximately 490 LB-FT.
- Compression ratio: 10.5:1.
- Other differences:
- More aggressive camshaft.
- Different pistons, with valve reliefs.
- Special dual-point distributor.
- A deep oil pan and a K-frame skid plate for protection.
How much horsepower does a 1970 Cuda 440 six pack have?
The Cuda had the 383ci 335HP as the standard engine. Options included the 440ci four-barrel 375HP Super Commando, the 440ci six-barrel Super Commando Six Pak with 390HP, and the 425HP 426ci Hemi.
Which is faster, 426 Hemi or 440 Six Pack?
Similar Treatment To The Hemi Does Change Things
We're not just blowing smoke when we say the 440 Six-Pack was faster than the 426 Hemi cars. Going back to Ronnie Marin's 12.90 run with an A12 Plymouth Road Runner, a similarly equipped 426-Hemi-powered model achieved a 13.6 quarter-mile run.
How much horsepower does a 440 6 pack have?
The Chrysler 440 "Six Pack" engine is factory rated at 390 horsepower and 490 lb-ft of torque, achieved by using a unique three-carburetor setup instead of a single one. This high-output version of the 440 V8 also features a higher compression ratio of 10.5∶110.5 colon 110.5∶1 compared to the standard 440's 9.5∶19.5 colon 19.5∶1.
- Horsepower: 390 hp @ 4,700 rpm
- Torque: 490 lb-ft @ 3,200 rpm
- Carburetor setup: Three two-barrel carburetors
- Compression ratio: 10.5:1
- Other features: Stiffer valve springs, chrome-moly piston rings, and chrome valve stems
