Cummins vs Duramax vs Power Stroke: Heavy-Duty Diesels Compared

Ram's 6.7L Cummins is an inline-six rated at 430 hp and 1,075 lb-ft in 2025–2027 heavy-duty pickups. GM's 6.6L Duramax V8 makes 470 hp and 975 lb-ft, and Ford's 6.7L Power Stroke V8 makes 475 hp and 1,050 lb-ft, or 500 hp and 1,200 lb-ft as the High Output. Ford currently publishes the highest tow ratings.

By CarWhere Research · Updated November 3, 2026

Current ratings side by side

Heavy-duty pickup diesel engines: layout, manufacturer-rated horsepower and torque, and transmission
Engine	Trucks	Layout	Output (hp / lb-ft)	Transmission
6.7L Cummins High Output	Ram 2500 / 3500 (2025–2027)	Inline-6, cast-iron block and head	430 hp / 1,075 lb-ft	8-speed TorqueFlite HD
6.6L Duramax L5P	Chevrolet Silverado HD / GMC Sierra HD (2024–)	90° V8, cast-iron block, aluminum heads	470 hp / 975 lb-ft	Allison 10-speed
8.3L Duramax (new for 2027)	Silverado HD / Sierra HD (2027, available)	V8	555 hp / 1,230 lb-ft	—
6.7L Power Stroke	Ford F-250 – F-450 Super Duty (2026)	90° V8, compacted graphite iron block, aluminum heads	475 hp / 1,050 lb-ft	10-speed TorqShift
6.7L High Output Power Stroke	Ford F-250 – F-450 Super Duty (2026)	90° V8, compacted graphite iron block, aluminum heads	500 hp / 1,200 lb-ft	10-speed TorqShift

Ram has listed only the High Output Cummins for its 2500 and 3500 pickups since 2025; the 360-hp version is a Chassis Cab engine. Engine histories: L5P Duramax, 6.6L Duramax generations and 6.7 Power Stroke.

Maximum towing by truck class

Maximum manufacturer-published diesel towing for 2026 heavy-duty pickups, in pounds
Class	Ram (Cummins), lb	Chevrolet (Duramax), lb	Ford (Power Stroke), lb
2500 / F-250, conventional	20,000	20,000	22,000
2500 / F-250, 5th-wheel or gooseneck	20,000 (Ram maximum)	22,050	23,000 (H.O.)
3500 / F-350, maximum (dually, gooseneck)	36,610	36,000	38,000 (H.O.)
2027 announced maximum	37,020 (3500, preliminary)	38,000 (with 8.3L)	—

Ram 2026 Ram 2500/3500 pages and 2027 Heavy Duty release; Chevrolet 2026 Silverado HD trailering charts and GM's 2027 HD release; Ford 2026 RV & Trailer Towing Guide. Ford's F-450 pickup reaches 40,000 lb with the 40K Gooseneck Tow Package. GMC Sierra HD ratings are similar to Silverado HD — see Silverado HD trim levels and towing and Ford Super Duty trim levels.

How the designs differ

Cummins: a long-stroke inline-six built by Cummins Inc. and used in Ram pickups since 1989; the 6.7L replaced the 5.9L during the 2007 model year. Inline-sixes are naturally balanced and the design favors low-rpm torque.
Duramax: GM's 6.6L V8, developed with Isuzu and in Silverado/Sierra HD trucks since 2001; the current L5P arrived for 2017 and was uprated to 470 hp for 2024. GM adds the 8.3L V8 for 2027.
Power Stroke: since 2011, a Ford-designed 6.7L V8 with the exhaust and turbocharger mounted in the engine valley (“inboard exhaust”) and a compacted graphite iron block.
All three use diesel particulate filters and SCR with diesel exhaust fluid (DEF) to meet emissions rules, so DEF refills and aftertreatment maintenance apply to every modern heavy-duty diesel.

Resale: 2500-class trucks in CarWhere live listings

Median used asking price and percent below the median new price, 2500-class trucks, by age
Truck	New median (USD)	3 years old: below new (%)	5 years old: below new (%)
Ram 2500 (Cummins or HEMI)	$75,299	37.8%	47.7%
Chevrolet Silverado 2500HD	$70,551	38.8%	43.4%
Ford F-250 Super Duty	$86,182	35.6%	46.4%

CarWhere live-listing depreciation study, data as of 2026-10-25. Model-level medians mix gas and diesel trucks, trims and cabs, so they show the truck line rather than the engine.

Before you buy a used diesel truck

Model-year history matters more than the badge. Read Ram 2500 years to avoid, Ram 3500 years to avoid and Ram reliability by model, then compare trucks head to head in Ram 2500 vs Ford F-250. Ram configuration details are on the Ram 2500 build sheet and Ram 3500 build sheet pages.

Buying a Cummins Ram? Confirm the engine and axle

A Ram heavy-duty can leave the factory with a HEMI or a Cummins, several axle ratios and different tow packages — the badge alone does not tell you which. Check the exact factory options of the truck before you buy. Enter the VIN on the Ram build sheet page: the availability check is free, and you pay $9.99 only if detailed build data exists for that truck.

Ram build sheet by VIN

Free availability check first · $9.99 one-time only if detailed build data exists for the VIN · no subscription

FAQ

Which is more powerful, the Cummins, Duramax or Power Stroke?

For 2026 pickups, Ford’s 6.7L High Output Power Stroke leads at 500 hp and 1,200 lb-ft. The 6.6L Duramax makes 470 hp and 975 lb-ft, and Ram’s 6.7L Cummins High Output makes 430 hp and 1,075 lb-ft. For 2027 GM adds an available 8.3L Duramax rated at 555 hp and 1,230 lb-ft.

What is the main difference between the Cummins and the Duramax?

Layout and supplier. The Cummins is a 6.7-liter inline-six built by Cummins Inc. for Ram, with a cast-iron block and head; the Duramax is a 6.6-liter V8 used by Chevrolet and GMC. The inline-six makes more torque (1,075 vs 975 lb-ft); the V8 makes more horsepower (470 vs 430 hp).

Cummins vs Power Stroke: which tows more?

Ford’s published maximums are higher. In 2500-class trucks, the F-250 diesel is rated up to 23,000 lb gooseneck versus 20,000 lb for the Ram 2500. In one-tons, an F-350 dually reaches 38,000 lb gooseneck versus 36,610 lb for the 2026 Ram 3500; Ram lists 37,020 lb (preliminary) for 2027.

Which diesel is the most reliable?

There is no single answer — each has documented issues by generation, such as high-pressure fuel pump concerns on some Power Stroke and Duramax years and emissions-system faults common to all modern diesels. Check model-year history for the exact truck, its maintenance records and its open recalls rather than relying on brand reputation.

Is the Cummins only available in Ram trucks?

Among pickups currently sold new in the US, yes — Ram is the only brand offering the 6.7L Cummins. Cummins engines also power many medium- and heavy-duty commercial vehicles. Ram also uses a lower-rated 360-hp, 800 lb-ft version of the 6.7L Cummins in its Chassis Cab trucks.

Sources

Ram — What’s new for 2027: Ram Heavy Duty (ramtrucks.com) — Cummins HO 430 hp / 1,075 lb-ft; preliminary 2027 ratings 20,000 lb (2500), 37,020 lb (3500)
Ram — 2026 Ram 3500 (ramtrucks.com) — 36,610 lb maximum towing, 430 hp
Stellantis — 2026 Ram Chassis Cab press kit — Chassis Cab Cummins 360 hp / 800 lb-ft
Chevrolet — 2026 Silverado 2500 HD trailering chart — 20,000 lb conventional, 22,050 lb 5th-wheel/gooseneck (Duramax)
Chevrolet — 2026 Silverado 3500 HD trailering chart — 36,000 lb gooseneck (Duramax dually)
GM Newsroom — Duramax 8.3L Turbo-Diesel V8 (2027 HD, Sep 2026) — 555 hp / 1,230 lb-ft; up to 38,000 lb gooseneck
Ford — 2026 Super Duty specifications (ford.com) — 6.7L 475 hp / 1,050 lb-ft; H.O. 500 hp / 1,200 lb-ft
Ford — 2026 RV & Trailer Towing Guide (revised 11-24-25) — F-250 23,000 lb gooseneck; F-350 DRW 38,000 lb; F-450 40,000 lb
CarWhere — Car depreciation by model (live-listing study)

Ratings are manufacturer-published and were read on November 3, 2026. Ram labels its 2027 tow ratings preliminary. Tow figures are maximums for properly equipped trucks; the rating for a specific truck depends on cab, bed, axle ratio, hitch and options.