Three different engines are offered on the HD trucks. A 6.0L V8, making 345 horsepower and 380 lb-ft of torque, is standard across the HD line, while an 8.1L V8 with 330 horsepower and 450 lb-ft is optional, along with a new version of the 6.6L Duramax turbo-diesel V8, making 360 horsepower and 650 lb-ft of torque. The diesel comes with an intake-air heater to help reduce smoke and emissions when the engine is cold.
Depending on the model, the engines can be mated with a five-speed manual transmission, four-speed Hydra-Matic automatic, or six-speed Allison automatic. The five-speed manual is offered on all 2500HD models but optional only on some of the 3500 variants.
The HD trucks are available in three box lengths, three cab styles, and in 2WD or 4WD for each. 2500HD models pair the crew cab with either the short or long box, while the regular cab comes only with the long box and the extended cab comes with either the standard or long box. 3500 models come only with the long box, in regular cab, extended, or crew cab variants.
The 2500 models can haul payloads of up to 4,058 pounds, while 3500 models can take payloads of up to 5,511 pounds.
3500 models come in SRW (single rear wheel) models, along with DRW (double rear wheel) variants that provide improved stability while towing heavy loads. Properly equipped, the DRW model can pull a trailer up to 13,000 pounds with a standard hitch and up to 16,000 pounds with a fifth-wheel hitch.
Like the light-duty Silverado Classic, the HD Silverados vary rather dramatically inside as well, from the very basic Work Truck (WT) trim all the way up to the top LT2 and LT3 equipment levels. The LT3, for example, includes dual-zone automatic climate control, cruise control, leather power seats, steering wheel controls, an overhead console, and a high-end audio system with six-disc changer. Options include some more interior items such as power-adjustable pedals, and a reverse sensing system, but the options list is long and mainly includes serious gear to outfit the HD for duty, such as with skid plates or a snow-plow prep package.