For 2026 heavy-duty pickups, Ram’s 6.7L Cummins High-Output diesel is rated at 430 hp and 1,075 lb-ft, while Chevrolet’s 6.6L Duramax diesel is rated at 470 hp and 975 lb-ft. In other words, the Cummins leads by 100 lb-ft of peak torque, and the Duramax leads by 40 hp. Those are manufacturer ratings—not proof that one truck accelerates or tows better in real use.
2026 Cummins and Duramax specifications
This comparison is specific to the 2026 Ram Heavy Duty’s 6.7L Cummins High-Output inline-six and the 2026 Chevrolet Silverado HD’s 6.6L Duramax V8. Engine ratings vary by model year and variant, so they should not be applied to every truck that has carried either engine name.
| 2026 engine and application | Configuration | Manufacturer-rated output | Transmission pairing |
|---|---|---|---|
| Ram 6.7L Cummins High-Output, Heavy Duty | Inline-six turbo-diesel | 430 hp and 1,075 lb-ft | TorqueFlite HD eight-speed automatic |
| Chevrolet 6.6L Duramax, Silverado HD | V8 turbo-diesel | 470 hp and 975 lb-ft | 10-speed Allison automatic |
Ram’s figures appear in its 2025 chart for 2026 Ram Heavy Duty models; Chevrolet lists the Duramax output and transmission on its 2026 Silverado HD specifications page. These are published specifications, not results from a matched independent test.
What the horsepower and torque difference means
Cummins: higher peak torque
The Cummins High-Output is rated at 1,075 lb-ft, 100 lb-ft above the Duramax’s published 975 lb-ft. That is a comparison of peak ratings alone; it does not establish how much usable power either truck delivers at a particular engine speed or under a particular load.
#1 Best Overall
- Diesel Engine: 196 cc displacement, four-stroke, 2.2 kW power, 3000 rpm; powerful performance, suitable for heavy-duty tasks; 3-liter (126.8-ounce) fuel tank supports extended operation without frequent refueling, ideal for use on farms or in workshops.
- Single-cylinder air-cooled diesel engine: Equipped with a forced air cooling system; Ventilation slots help reduce temperature and extend engine lifespan; a low-noise muffler creates a comfortable working environment.
- 3 HP diesel engine: Features a high-end aluminum alloy construction; shot-blasted and powder-coated for a smooth, durable finish; excellent rust resistance; equipped with a threaded flow diesel system and single-valve fuel injection, ensuring low emissions and stable operation.
- Manual starting mechanism: Features a simple recoil starter system for easy engine startup; Ergonomically designed throttle lever; pressure relief cap for easy starting; air filter with paper filter element for thorough filtration and easy maintenance.
- Wide range of applications: 4-cylinder, fuel-efficient diesel engine with a fuel consumption rate of ≤280 g per kWh; suitable for micro tillers, water pumps, grinders, plate compactors, small tractors, concrete mixers, and more.
Duramax: higher horsepower
The Duramax is rated at 470 hp, 40 hp above the Cummins High-Output’s 430 hp. Horsepower and torque describe different aspects of engine output, and neither figure by itself predicts a truck’s performance across every speed, gear, or towing condition.
The transmissions are part of the comparison
Ram pairs this Cummins variant exclusively with the TorqueFlite HD eight-speed automatic, while Chevrolet lists the Duramax with a 10-speed Allison automatic. Because these are different engine-and-transmission packages, the ratings alone cannot settle questions about acceleration, shift behavior, or towing feel. Those require independent testing of comparable trucks under the same conditions.
Rank #2
- Best kit for the most popular truck/tractor engines for use on Cummins 5.9, Ford Powerstroke 6.0L, 6.4L, 6.7L, 7.3L (both styles), International Navistar 6.9/7.3L, International Navistar 4.5L VT275, 6.0L VT365E, 6.4L MaxxForce 7
- Compatible with Repair and Replace on Cummins V6, V8, V12, 855, 5.9L, Detroit Diesel 53, 71, 92, 110, 149, V53, V71 with low or high clamp inj. hold down
- Compatible with Repair and Replace on GM Duramax 4.3/5.7/6.2/6.5L/6.6L , CAT D-336, 1674, 1676, 3406, 3408, 3412; PERKINS 4.203, 4.236, 4.248, 6.354, 8.540
- Compatible with Repair and Replace for Mercedes 12MM, 18MM, CASE, DEER, MACK, PERKINS, ONAN, Allis-Chalmers, + more, see list product details
- Dual scale 80 mm diameter Liquid Filled Gauge 0 - 1000 Lb/In and 0 - 70 bar, 14.5" long hose. Built in Check valve
Towing ratings depend on the exact truck
Chevrolet advertises up to 36,000 lb of maximum available trailering for the 2026 Silverado HD, subject to qualifying equipment and configuration. That is a manufacturer-stated maximum, not the rating for every Silverado HD. Ram’s 2026 chart likewise gives towing and payload ratings by specific truck configuration rather than one universal number.
Before comparing two trucks, check the rating for each exact build. Cab, bed, axle ratio, drive configuration, hitch and other equipment can affect capacity. Use the current manufacturer chart, then verify the truck’s certification label and owner documentation. A maximum trailer rating does not automatically tell you the payload available for passengers and cargo or the allowable tongue or fifth-wheel pin weight.
The Tool Desk
Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Rank #3
- DOC'S DIESEL MAINTENANCE KITS - Doc’s Diesel Maintenance Kits save you time and money by giving you the filters you need in one convenient package. No more running around trying to find the right parts. Just grab a kit and get the job done! Swapping filters on time keeps your truck running strong and efficient, and with our Maintenance Kits, it’s easier than ever.
- FITMENT - Compatible with Chevrolet/GMC 6.6L Duramax 2500HD, 3500HD 2020-2025
- INTERCHANGE - Doc's Diesel Chevrolet/GMC 6.6L Duramax Filter Maintenance Kit 2020-2025 includes (1) Fuel Filter (DGF429) - Replaces AC/Delco TP1015, Replaces Wix WF10451, Replaces Premium Guard DF99173, Replaces Purolator F21393. (1) Oil Filter (D11878) - Replaces GM 12684038, Replaces AC/Delco PF26, Replaces Wix WL10454, Replaces Baldwin B7449, Replaces Premium Guard PG9952EX. (1) Engine Air Filter (DPA11888) - Replaces GM 84554703, Replaces Wix WA11057, Replaces Baldwin PA10426, Replaces Premium Guard PA99537, Replaces Purolator TA31515. (1) Cabin Air Filter (D3932C) - Replaces GM 13508023, Replaces AC Delco CF185, CF1184C, Replaces Baldwin PA10369, Replaces Premium Guard PC4211C
- THIRD PARTY TESTING - Doc's Fuel Filter (DGF429): 3 Micron @ 98.13% Efficiency Rating. Doc's Oil Filter (D11878): 25 Micron @ 99% Efficiency Rating. Doc's Engine Air Filter (DPA11888): 99.25% / 344.2G Dust Holding Capacity. Doc's Cabin Air Filter (D3932C): Electrostatic media stops particles down to .001 Microns
- REPLACEMENT GUIDELINES - Above all recommendations, change according to your vehicle’s manufacturer's warranty. Fuel/Water Separators: Every 5,000-10,000 miles or 15,000 miles maximum. Oil Filters: Every 5,000-7,000 miles or 10,000-15,000 miles maximum. Transmission Filters: Every 25,000-50,000 miles or 60,000 miles maximum. Engine Air Filters: Every 5,000-10,000 miles or 12,000 miles maximum. Cabin Air Filters: Every 15,000 miles or 12 months maximum.
Diesel upkeep and ownership costs
DEF and routine maintenance
Chevrolet’s Duramax Diesel FAQ says diesel ownership includes DEF refills and routine maintenance, and directs owners to the vehicle manual for service intervals. DEF (Diesel Exhaust Fluid) is injected into the exhaust system in vehicles equipped with selective catalytic reduction; it is not a fuel additive. Follow the manual for the correct fluid specification and service guidance. This is general Chevrolet diesel guidance, not a comparison of Cummins and Duramax service schedules.
Fuel economy, reliability and total cost
The manufacturer sources cited here do not establish which engine delivers better fuel economy, lasts longer, or costs less to own over time. Engine layout, peak output and warranty wording are not enough to determine those outcomes. A useful comparison would require equivalent trucks, comparable loads and routes, fuel and DEF use, maintenance records, and a defined period or mileage.
Quick Recap
Best Value
- Wide Compatibility - Fuel Injector Caps designed for fuel rail diagnostics in 2003-2022 Cummins, 2001-2022 Duramax, and 2008-2022 Ford engines.
- Efficient Functionality - Effectively blocks the fuel supply to cylinders or seals the common rail pipe, aiding in the identification of faulty diesel injectors and diagnosing engine knock sounds.
- Easy-to-Follow Instructions - Identify the faulty cylinder by removing the diesel fuel injection line from one cylinder at a time and installing the cap on the fuel rail. Increased fuel pressure indicates the faulty injector.
- High-Quality Construction - Made from full carbon steel with an anti-rust finish. These fuel line caps feature a galvanized surface for durability and resistance to breakage and deformation, ensuring a long service life.
- Important Note - Multiple fuel pressure block-off tools can be helpful, as several injectors returning small amounts of fuel can mimic the symptoms of a single injector returning excessive fuel.
Rank #4
- Replacement part numbers: CA10261, PA4318, PA6314, 88930, 46930, LAF8837, 53034051AB, 68517554AA, 53034249AA, P616743, AF27684, AF1326, E-0784, A3170C, A8837, A56314, 335005
- Fit for Dodge Ram 2500 & 3500 L6 6.7L Diesel 2007-2010, for Dodge Ram 4500 & 5500 L6 6.7L Diesel 2008-2010, for Ram 2500 3500 4500 5500 L6 6.7L Diesel 2011-2023, for Ram 2500 3500 4500 5500 V8 6.4L Gas 2019-2022, for Sterling Truck Bullet 45 55 6.7L 2008-2010
- Advantages: This air filter using microporous filtering media, it efficiently attracts dirt without obstructing the airflow, captures debris, and prevents debris and dirt from entering the engine interior
- Packaging list: 1×air filter
- Warm reminder: Our air filter can reach a maximum mileage of 12000 miles. It is recommended to replace the filter after driving 10000-12000 kilometers. Please confirm whether the model is what you need before purchasing
How to compare two trucks you might buy
- Match the model year and engine variant. Confirm that the Ram has the 6.7L Cummins High-Output and that the Chevrolet has the 6.6L Duramax for the model year being considered.
- Compare the complete powertrain. Note each engine’s published horsepower and torque along with its transmission; do not treat the engine rating as a real-world performance test.
- Find ratings for the exact configurations. Match cab, bed, drive, axle and equipment, then check towing and payload in the current manufacturer chart.
- Verify the load limits for your trailer. Check the truck’s certification label and owner documentation, including payload and applicable tongue or pin-weight limits—not just the headline maximum trailer rating.
- Estimate ownership using your own use case. Compare fuel and DEF use, maintenance and repair costs over a stated mileage, warranty terms for the model year, and access to local service. The published figures above do not identify a winner on those factors.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
