The Duramax L5P vs Ford 6.7 Power Stroke debate is one of the most heated rivalries among diesel truck owners. Since the L5P Duramax arrived in 2017 alongside continuous updates to the 6.7L Power Stroke, both engines have proven themselves as reliable workhorses -- but they take different approaches to power, efficiency, and durability. This in-depth reliability comparison covers everything from towing capacity and fuel economy to long-term maintenance costs, so you can decide which diesel engine is right for your truck.
Duramax L5P vs Ford 6.7 Power Stroke: Quick Comparison
| Specification | Duramax 6.6L (L5P) | Power Stroke 6.7L |
|---|---|---|
| Configuration | V8 Turbo Diesel | V8 Turbo Diesel |
| Horsepower | 470 HP | 500 HP |
| Torque | 975 lb-ft | 1,200 lb-ft |
| Transmission | Allison 10-speed | TorqShift 10-speed |
| Max Towing | 36,000 lbs | 40,000 lbs |
| Fuel Economy | ~15-18 MPG | ~14-17 MPG |
| DEF Required | Yes | Yes |
L5P Duramax and 6.7 Power Stroke Engine Overview
Chevrolet/GMC Duramax 6.6L (L5P)
Introduced in 2017, the L5P Duramax is a joint venture between GM and Isuzu. It features a new injection system, redesigned turbocharger, and improved emissions controls. The L5P is known for its smooth power delivery and refinement.
Key Features: Denso high-pressure fuel system, variable geometry turbo, aluminum heads, compacted graphite iron block.
Ford Power Stroke 6.7L
Ford's third-generation 6.7L Power Stroke (introduced 2020+) is an in-house design featuring new high-pressure injection, larger turbo, and improved exhaust brake. It's the most powerful diesel engine in its class.
Key Features: 36,000 PSI fuel injection, dual sequential turbos (some models), forged steel crankshaft, exhaust brake standard.
Power Stroke vs Duramax: Power and Performance
Winner: Ford 6.7 Power Stroke
The 6.7L Power Stroke produces more horsepower (500 vs 470) and significantly more torque (1,200 lb-ft vs 975 lb-ft). This advantage is noticeable when:
- Towing heavy loads up steep grades
- Accelerating with a loaded trailer
- Hauling maximum payload
However, for most real-world towing under 20,000 lbs, both engines feel equally capable.
Ford Diesel vs Duramax: Reliability and Longevity
Tie -- Both Are Excellent
The reliability comparison between the L5P Duramax and current 6.7L Power Stroke shows both engines holding up extremely well over time. Common high-mileage reports:
- Duramax L5P: 200,000-400,000+ miles with proper maintenance
- Power Stroke 6.7L: 200,000-350,000+ miles with proper maintenance
Maintenance Is Key
Both engines require premium diesel fuel, quality oil, DEF fluid, and regular fuel filter changes. Neglecting maintenance dramatically shortens diesel engine life regardless of brand.
Duramax vs Power Stroke Fuel Economy
Winner: Duramax L5P (Slightly)
The Duramax typically achieves 1-2 MPG better fuel economy:
- Duramax: 14-16 city / 18-21 highway (unloaded)
- Power Stroke: 13-15 city / 16-19 highway (unloaded)
When towing, both engines see significant fuel economy drops (8-12 MPG typical), and the gap narrows.
Transmission: Allison vs TorqShift
Winner: Duramax (Allison)
The Duramax is paired with the legendary Allison transmission, considered the gold standard in heavy-duty automatic transmissions. Benefits include:
- Proven reliability in commercial applications
- Smooth, confident shifts even under load
- Excellent heat management when towing
- Strong aftermarket support
Ford's TorqShift 10-speed is also excellent and well-suited to the Power Stroke, but the Allison's reputation gives Chevy an edge with many buyers.
Towing Capability: Ford Diesel vs Duramax
Winner: Power Stroke
Ford's max towing numbers edge out Chevy:
- F-350 DRW: Up to 40,000 lbs gooseneck
- Silverado 3500 DRW: Up to 36,000 lbs gooseneck
The Power Stroke's extra torque translates to more confident towing at maximum capacity. However, both trucks far exceed what most owners actually tow.
Long-Term Ownership Costs: L5P vs 6.7 Power Stroke
| Cost Factor | Duramax | Power Stroke |
|---|---|---|
| Oil Change | $100-150 | $100-150 |
| Fuel Filters | $50-100 | $60-120 |
| DEF (per gallon) | $8-15 | $8-15 |
| Injector Replacement | $3,000-5,000 | $4,000-6,000 |
| Turbo Replacement | $2,500-4,000 | $3,000-5,000 |
Overall ownership costs are similar, though Power Stroke repairs tend to be slightly more expensive due to Ford's proprietary design.
Which Should You Buy?
Choose the Duramax L5P If You Want:
- Legendary Allison transmission
- Slightly better fuel economy
- Smoother, quieter operation
- Lower repair costs (slightly)
- GMC Denali luxury option
Choose the 6.7 Power Stroke If You Want:
- Maximum towing capacity
- Most torque available
- Best-in-class exhaust brake
- Ford's extensive dealer network
- Highest resale value (typically)
If you're leaning toward a Ford Super Duty, read our F-250 vs F-350 comparison to decide on the right model. Already have your diesel truck? Browse our tire selection to find the perfect set for your build, or check out our lift kit catalog to take your truck to the next level.
Shop Diesel Trucks in Tampa
LR Wheels N Lifts carries both Duramax and Power Stroke trucks. Browse our current inventory or schedule a visit to see them in person.
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