General Motors' latest generation small-block V8, particularly the 6.6L L8T, delivers robust power and torque designed for heavy-duty applications.
Core Performance Specifications
- Engine Type: 6.6L OHV V8 (Pushrod)
- Bore x Stroke: 103.25 mm x 99 mm
- Compression Ratio: 10.8:1
- Fuel Delivery: Direct Injection
Key Output Figures
The naturally aspirated L8T generates:
- Horsepower: 401 hp @ 5200 rpm
- Torque: 464 lb-ft @ 4000 rpm
Note: Final output varies slightly depending on vehicle calibration (e.g., Silverado HD vs Sierra HD).
Architecture & Technology
Built on GM's proven Gen V small-block foundation featuring:
- Aluminum Cylinder Heads: Improve weight and thermal efficiency.
- Rotocast A356 Aluminum Exhaust Manifolds: Enhanced durability under high heat.
- Forged Steel Crankshaft & Powdered Metal Rods: Withstand high cylinder pressures.
- EcoTec3 Engine Technologies: Includes active fuel management (cylinder deactivation) and variable valve timing for efficiency.
Targeted Applications
Optimized for demanding duties in:
- Heavy-Duty Trucks: Chevrolet Silverado 2500HD/3500HD, GMC Sierra 2500HD/3500HD.
- Commercial Chassis Cabs: Low Cab Forward platforms.
- Motorhomes: Large Class A models requiring high torque.
Strength & Purpose
This V8 prioritizes:
- Sustained High Torque: Significant low/mid-range torque enables substantial towing (up to 36,000 lbs max) and payload capacity.
- Durability: Design emphasizes longevity under severe workloads.
- Real-World Usability: Power delivery focuses on work capability rather than peak speed.
While not competing with high-revving performance engines, the new GM V8 excels in its core mission: reliable, high-torque propulsion for the heaviest-duty applications.
