Spied! 2010 Dodge Ram Heavy Duty Mega Cabs With 8-Foot Boxes

While Chrysler is showing off custom versions of the 2009 Dodge Ram 1500 light-duty pickup at the SEMA show in Las Vegas, we're just two months from the world debut of the new 2010 Dodge Ram 2500 and 3500 heavy-duty rigs at the Detroit auto show.

Following earlier pictures, our spies have caught single-rear-wheel and dual-rear-wheel Mega Cab models out for their final shakedowns. Both have 8-foot beds, which is a new option for 2010. Adding the 8-foot box should increase the Mega Cab's attractiveness to fifth-wheel towers. Today's 6-foot, 3-inch standard box doesn't leave enough room between a fifth-wheel trailer and the cab during tight turns.

Camouflage over the rear wheel wells of the dually truck hides new fenders that industry sources say are stamped into the sheet metal, like the Chevrolet Silverado HD dually's rear haunches, instead of clipped-on plastic arches.

The 2010 Ram 2500 and 3500 aren't expected to see major changes to their gas or diesel powertrains. For 2009, the 5.7-liter Hemi V-8 was upgraded to 383 horsepower and 400 pounds-feet of torque. The gas-fired Hemi V-8 is expected to remain the base engine for the 2010 Ram 2500. The Ram 3500 is expected to carry over its 6.7-liter Cummins six-cylinder diesel engine. The 6.7-liter diesel already meets tough new 2010 federal emissions regulations that become mandatory on January 1, 2010.

The 2010 heavy-duty Rams' interiors will be based on the 2009 Dodge Ram half-ton's high-quality instruments, ergonomics and materials.