Chevrolet/GMC
The GM 2500/3500 twins Silverado HD and Sierra HD come standard with GM's 6.0L gas V-8. This engine is best suited for 3⁄4-ton trucks where towing isn't a concern. Upgrades start with the 8.1L gasoline V-8 based on Chevrolet's venerable big-block engine. This decades old, yet rugged and reliable design makes more horsepower and torque than the Ford and Dodge V-10 gasoline engines. Stepping up to GM's diesel offering gets you the Isuzu-engineered 6.6L V-8 that pumps out 300 hp and 520 lb-ft of torque. Even though this engine is one of our favorite GM truck powerplants of all time, mating it to the optional Allison-built automatic transmission makes it even better. This transmission also can be ordered with the 8.1L engine and is based on Allison technology it perfected while building heavy-duty truck automatic transmissions.
GM 6.0L Gasoline Click image...
GM 6.0L Gasoline
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GM 6.0L Gasoline
Engine type: V-8, cast-iron block, aluminum heads
Bore x stroke, in: 4.00 x 3.62
Displacement, ci/L: 366/6.0
Compression ratio: 9.4:1
Valve gear: 2 valves/cyl, OHV
Fuel induction: Sequential multiport
Horsepower, hp @ rpm: 300 @ 4400
Torque, lb-ft @ rpm: 360 @ 4000
Recommended fuel: Unleaded regular
Max GCWR, lb: 16,000
Max towing capacity, lb: 10,500
Option price: Standard
GM 8.1L Gasoline Click image...
GM 8.1L Gasoline
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GM 8.1L Gasoline
Engine type: V-8, cast-iron block and heads
Bore x stroke, in: 4.25 x 4.37
Displacement, ci/L: 496/8.1
Compression ratio: 9.1:1
Valve gear: 2 valves/cyl, OHV
Fuel induction: Sequential multiport
Horsepower, hp @ rpm: 340 @ 4200
Torque, lb-ft @ rpm: 455 @ 3200
Recommended fuel: Unleaded regular
Max GCWR, lb: 22,000
Max towing capacity, lb: 15,800
Option price: $850
GM 6.6L Turbodiesel Click...
GM 6.6L Turbodiesel
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GM 6.6L Turbodiesel
Engine type: V-8, cast-iron block, aluminum heads
Bore x stroke, in: 4.06 x 3.90
Displacement, ci/L: 403/6.6
Compression ratio: 17.5:1
Valve gear: 4 valves/cyl, OHV
Fuel induction: Direct injection, high-pressure common rail
Horsepower, hp @ rpm: 300 @ 3100
Torque, lb-ft @ rpm: 520 @ 1800
Recommended fuel: Diesel
Max GCWR, lb: 22,000
Max towing capacity, lb: 15,800
Option price: $4810 ($1200 for Allison 1000)