Dodge Truck has unveiled its 2010 Ram Heavy Duty pickups and Chassis-Cab models that feature bolder styling and stylish interiors from the '09 Ram 1500, plus a four-door crew cab for true six-person capacity.

The Ram 2500 and 3500 pickups and 3500, 4500 and 5500 Chassis-Cab trucks also have updated engines, and some versions have 500 to 600 pounds more payload and towing capacity.

Ram HDs have smoother contours for better aerodynamics, and get larger grilles and taller hoods than 1500s to reflect the HDs' stronger capabilities. Dual-rear-wheel pickups have one-piece bed-side and fender panels instead of the separate bed-and-fender pieces of previous models.

HD Pickups are available with a two-door Regular Cab and a four-door Crew Cab, with full-length rear doors and more back-seat leg room than the four-door Quad Cab, which is being dropped (but continues on the Ram 1500), plus the extended four-door Mega Cab. Chassis-cab models come with Regular and Crew Cabs; the crew version will make Ram HDs more competitive as multi-person crew carriers for users of work trucks.

Interiors are like those in the Ram 1500s, with nicer materials and a more upscale feel for all trim levels. They also feature multiple storage compartments and numerous electronic infotainment options. Trim levels include the base ST, which is standard with manual windows and mirrors but is now available with power windows, mirrors and locks. The SLT and Laramie are the more deluxe levels for HDs.

The 2500 and 3500 pickups are standard with the 5.7-liter Hemi V-8 with 383 horsepower and 400 pounds-feet of torque, and the 6.7-liter Cummins Turbo Diesel with 350 horsepower and 650 pounds-feet is optional. The 3500 Chassis-Cab also uses both engines. The Cummins already meets federal exhaust emissions limits for 2010 and needs no changes.

Heavier Chassis-Cab models come only with the Cummins, but with 610 pounds-feet and, starting in January '10, using selective catalytic reduction to meet the new emissions limits. The C-C 3500 will also use the SCR version of the Cummins.

2010-model Ram HDs will begin arriving at dealers this fall.