In addition to the new diesel (and 6.2-liter gas) engines, other significant changes to the Ford include a new six-speed automatic, revised exterior styling, towing improvements, slight spring retuning, and interior upgrades. Inside, most of the changes are subtle with the exception of a new, huge reconfigurable center armrest, along with a new optional electronic information center. The 2010 Ram HD sports an entirely new interior and exterior, further separating it from the smaller, lighter-duty Ram 1500. It also boasts reengineered front-end springs that provide more load-carry capacity for all 4x2 and 4x4 configurations. Inside, the Ram HD offers a vastly improved layout with much better materials and touch surfaces, as well as a new center stack and deep center console.

Both our Ford Super Duty F-250 and Dodge Ram HD 2500 testers are four-wheel drive, dressed in topline trim (King Ranch and Laramie), crew cabs, short beds riding on live axles with coil springs in front and leafs in the rear, and each uses a six-speed automatic. They aren't identically equipped, though: the Super Duty has 3.55:1 ring-and-pinion gears (Ram HD has 3.73:1), 20-inch wheels, and 275/65R20 tires (Ram HD has 17-inch rims and 265/70R17 tires), an extra 500 pounds in actual weight in the Ford, and a 10,000-pound GVWR (400 more than the Ram HD).

We took these heavyweight haulers north of Los Angeles, into the Central Coast's wine country, where we found a 60-mile drive loop of two-lane country roads plus freeway driving. Each truck expert drove both trucks over the same loop, running one set of loops empty, another loaded to each truck's maximum payload, and a third set of back-to-back loops towing a 7500-pound double-axle horse trailer .