Performance For what they are, GM's big vans are capable all-round performers. The 5.7-liter V-8 is deservedly the most popular engine, providing brisk takeoffs and adequate mid-range push with a light people/package load. It does lose steam up long grades, however, and a full load will dictate caution on short freeway on-ramps and when passing on two lane roads. Big vans are never close to being frugal, though GM has a competitive edge with its turbodiesel engine. Our last test model had the 5.0-liter gas V-8, which wasn't drastically slower than the 5.7 and averaged 14.3 mpg versus 12.7.
   Though even passenger models lack the ride control of most minivans, these GM rigs display little rough-road harshness and only minor float over crests and dips. They're also surprisingly refined. Mechanical ruckus is noticed because engines protrude into the front-seat area, but wind and road noise are low enough to allow conversing in normal tones up to 65 mph at least.
   Like other big vans, these are quite clumsy to drive, with a wide turning radius, copious cornering lean and modest grip--all par for this course. Overassisted steering hardly helps, but the GM products respond with reasonable confidence in lane changes and other quick maneuvers. Brakes have firm, satisfying pedal action, but high weight means only adequate stopping performance at best, this despite standard 4-wheel ABS.
   Accommodations Most full-size vans are used as commercial vehicles--even the passenger models--and GM's latest big vans were designed with that in mind. For example, the 7.4-liter and diesel V-8s were too bulky to move forward like the other engines, so they're set slightly to starboard to maximize leg room for--who else?--the driver. Similarly, the wide-opening back-end doors ease cargo handling, and the high-set taillamps are visible with the doors open, a safety plus on city streets. There's even a tough plastic rim protecting the aft edge of the roof, and a non-slip area on the front bumper to stand on while washing the windshield.
   Commercial or passenger model, wide-bottom front-door openings aid entry/exit, though step-in is still a bit lofty. Front footwells are long but not that wide, though no big van offers better leg space. Relatively compact engine housings leave sufficient walk-through space to the rear. The dashboard features legible round gauges, simple rotary-knob climate controls, and a big-button stereo--all close by for quick access on the move. Too bad the driver's power seat controls are on the front of the cushion and tough to reach.
   Passenger models offer generous rear room in all positions, and seats are firm and supportive. The rear benches are easy to unlatch, but too heavy for most people to move alone. Maximum available cargo volume is a whopping 317 cubic on extended models--more than competitive if not tops among big vans.
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