The Chevrolet Silverado 2500 HD III (K2XX) Regular Cab Long Box, equipped with the 6.0-liter V8 engine producing 301 horsepower and paired with an automatic transmission, and capable of running on Compressed Natural Gas (CNG), was a work-focused variant of Chevrolet’s heavy-duty pickup truck line. Produced for the 2015 and 2016 model years, this configuration occupied a middle ground within the 2500 HD lineup, offering a balance between capability, fuel flexibility, and cost. It was part of the third generation of the Silverado HD series (K2XX platform), representing a significant redesign focused on increased strength, improved refinement, and enhanced towing capacity compared to its predecessors.
Technical Specifications
| Brand | Chevrolet |
| Model | Silverado 2500 HD |
| Generation | Silverado 2500 HD III (K2XX) Regular Cab Long Box |
| Type (Engine) | 6.0 V8 (301 Hp) Automatic CNG |
| Start of production | 2015 |
| End of production | 2016 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Pick-up |
| Seats | 2 |
| Doors | 2 |
| Fuel Type | Petrol / CNG |
| Power | 301 Hp @ 5000 rpm |
| Power per litre | 50.4 Hp/l |
| Torque | 452 Nm @ 4200 rpm / 333.38 lb.-ft. @ 4200 rpm |
| Maximum engine speed | 6000 rpm |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | Vortec LC8 |
| Engine displacement | 5967 cm3 / 364.13 cu. in. |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 101.6 mm / 4 in. |
| Piston Stroke | 92 mm / 3.62 in. |
| Compression ratio | 9.6:1 |
| Number of valves per cylinder | 2 |
| Fuel injection system | Multi-port manifold injection |
| Engine aspiration | Naturally aspirated engine |
| Valvetrain | OHV, VVT |
| Engine oil capacity | 5.7 l / 6.02 US qt | 5.02 UK qt |
| Coolant | 15.5 l / 16.38 US qt | 13.64 UK qt |
| Fuel tank capacity | 136 l / 35.93 US gal | 29.92 UK gal |
| CNG cylinder capacity | 67 kg |
| Length | 5699 mm / 224.37 in. |
| Width including mirrors | 2035 mm / 80.12 in. |
| Height | 1976 mm / 77.8 in. |
| Wheelbase | 3393 mm / 133.58 in. |
| Front track | 1748 mm / 68.82 in. |
| Rear (Back) track | 1709 mm / 67.28 in. |
| Ride height (ground clearance) | 231 mm / 9.09 in. |
| Minimum turning circle (turning diameter) | 14 m / 45.93 ft. |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives the rear wheels of the vehicle. |
| Drive wheel | Rear wheel drive |
| Number of gears and type of gearbox | 6 gears, automatic transmission Hydra-Matic |
| Front suspension | Independent torsion bar, double wishbone |
| Rear suspension | Rigid axle suspension, Leaf spring |
| Front brakes | Ventilated discs, 350×40 mm |
| Rear brakes | Ventilated discs, 360×34 mm |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Cone worm with recirculation balls |
| Tires size | 245/75 R17; 265/70 R17; 265/70 R18; 265/60 R20 |
| Wheel rims size | 7.5J x 17; 8J x 18; 8.5J x 20 |
Powertrain & Engine Architecture
The heart of this Silverado 2500 HD variant was the Vortec LC8 6.0-liter V8 engine. This engine, a staple in Chevrolet’s truck lineup for many years, featured a cast iron block and aluminum cylinder heads. It utilized a multi-port fuel injection system for precise fuel delivery and incorporated Overhead Valve (OHV) technology with Variable Valve Timing (VVT) to optimize performance and efficiency. The LC8 produced 301 horsepower at 5000 rpm and 452 Nm (333.38 lb-ft) of torque at 4200 rpm. The engine was longitudinally mounted in the chassis. The transmission was a six-speed Hydra-Matic automatic, chosen for its durability and ability to handle the engine’s torque output. The addition of CNG capability allowed fleet operators and owners to take advantage of potentially lower fuel costs and reduced emissions, though it required a dedicated CNG tank and fuel system.
Driving Characteristics
The 6.0L V8 with the six-speed automatic provided a solid, if not particularly sporty, driving experience. Compared to the available 6.6-liter Duramax diesel engine, the 6.0L gasoline engine offered less torque, resulting in a lower maximum towing capacity. However, it was more responsive than the lower-output 4.8L V8. The automatic transmission’s gear ratios were tuned for work, prioritizing pulling power over fuel economy. Acceleration was adequate for everyday driving, but the truck felt most comfortable when cruising at highway speeds. The CNG capability didn’t significantly alter the driving characteristics, though it could slightly reduce available power depending on the CNG fuel pressure and engine management system calibration.
Equipment & Trim Levels
The Regular Cab Long Box 2500 HD with the 6.0L V8 and automatic transmission typically came standard with basic work-truck features. This included vinyl upholstery, a basic audio system, and manual windows and locks. Air conditioning was often standard, but higher-end features like power seats, a navigation system, and premium audio were typically optional. The CNG conversion was usually an upfit performed by a third-party installer, adding a dedicated CNG tank, fuel lines, and a fuel selector switch. Trim levels varied, but this configuration often served as a base for commercial fleets or buyers prioritizing functionality over luxury.
Chassis & Braking
The K2XX platform Silverado 2500 HD featured a fully boxed frame for increased rigidity and strength. The front suspension utilized an independent torsion bar setup with double wishbone components, while the rear suspension employed a traditional leaf spring design. This configuration was optimized for hauling and towing. Brakes consisted of ventilated discs at all four corners, with larger front discs (350x40mm) than the rear (360x34mm). An Anti-lock Braking System (ABS) was standard. Steering was accomplished via a cone worm with recirculation balls system, providing a robust and reliable feel.
Market Reception & Comparison
The Silverado 2500 HD with the 6.0L V8 and automatic transmission was generally well-received as a capable and affordable work truck. Critics noted its strong engine, comfortable ride (for a heavy-duty truck), and improved interior compared to previous generations. However, it was often overshadowed by the more popular Duramax diesel option, which offered superior towing capacity and fuel economy. The CNG variant appealed to a niche market of fleet operators and environmentally conscious buyers. Fuel economy was comparable to other gasoline-powered heavy-duty trucks, but the CNG option offered the potential for cost savings in areas with readily available and affordable CNG fuel.
Legacy
The Vortec LC8 6.0L V8 engine proved to be a durable and reliable powerplant, and examples continue to be found in service today. While not as sought-after as the Duramax diesel, the 6.0L gasoline engine remains a viable option for those seeking a capable and relatively affordable heavy-duty truck. The CNG-converted models, while less common, represent an early effort to diversify fuel sources in the commercial truck market. In the used car market, these Silverado 2500 HDs are often valued for their work-ready capabilities and relatively simple mechanical design, making them attractive to owners who prioritize practicality and affordability.
