A 353-hp 6.0L Vortec V-8 powers single rear-wheel (SRW) models, while "Big Dooley" DRW models have a 312-hp version of the 6.0L V-8. Both SRW and DRW versions are available with an optional 365-hp 6.6L Duramax diesel engine for extra towing capacity. Like all Silverados, the 3500HD is available in a wide array of bed sizes, wheelbases, drive types and cab sizes, as well as a variety of trim levels. Safety features include driver and passenger front air bags, tire pressure monitoring system (SRW only) and four-wheel antilock disc brakes. The Silverado 3500HD carries over from 2007 with few changes.