When it comes to serious hauling and towing, the Ram 3500 Heavy Duty is one of the most capable trucks available. Regular cab, crew cab, and extended-length Mega Cab styles are all available, and the Ram 3500 Heavy Duty models offer a choice between gasoline V8 and two power levels of diesel inline six-cylinder power. Naturally, you can upgrade to four-wheel drive or a more robust dual-rear-wheel axle configuration.