Heavy-duty pickup trucks like the 2007 Dodge Ram 3500 are draft horses, pure and simple. Dodges heavy-duty truck lineup actually consists of two models: the 2500 and 3500. The difference between the two mostly relates to capacity -- the 3500 can take on a heavier payload thanks to its stiffer suspension and optional dual-wheel rear axle. The current Ram 3500 design dates back to 2003. A significant powertrain upgrade is notable this year. A new 6.7-liter Cummins turbodiesel engine (late availability) replaces the previous 5.9-liter engine. It produces 350 hp at 3,000 rpm and an impressive 650 lb-ft of torque at 1,500 rpm. Antilock disc brakes are standard on the Ram 3500, and side curtain airbags are optional. Optional on the SLT and standard on the Laramie are power-adjustable pedals.