Not to be upstaged by crosstown rival Ford, GM recently unveiled the details of its 2007 Heavy-Duty pickups. Based on the all-new GMT900 architecture, the trucks feature many of the same upscale amenities and features that debuted in the SUVs and half-ton trucks. Silverado LTZ and Sierra SLT interiors mirror the car-like dashboard that was introduced on the Tahoe and Yukon.

Picking up on a popular feature that first appeared on the 2004 Ford F-150, extended-cab models feature available roll-down windows on the rear doors, a first for GM, and a feature also shared with the half-ton models.

Initial towing and hauling specifications focused mainly on the gasoline-engine model, possibly a tacit acknowledgement that Ford trumped them on the diesel side with the '08 Super Duty. GM is claiming a conventional towing capacity of 13,000 with a frame-mounted hitch, and up to 16,700 with a fifth-wheel "gooseneck" style hitch.

Regardless of capability or capacity, if you're just looking for power bragging rights, GM still has the upper hand. Even in compliance with the super-strict 2007 diesel emissions standards, the new "LMM" 6.6L Duramax engine cranks out 365 horsepower and 660 lb./ft. of torque, besting the new 6.4L Power Stroke by 15 horsepower and 10 lb./ft. respectively. Backing up the Duramax is the Allison 1000 six-speed transmission from last year's model.

The Vortec 6000 gasoline V-8 is backed up by a new HydraMatic 6L90 six-speed automatic transmission. Peak output for the engine is 353 horsepower and 373 lb./ft. of torque.

Unlike the coil-spring front suspension and rack & pinion steering featured on the new half-ton models, the heavy-duty models continue to use a recirculating ball steering system and torsion bar front suspension.