BIG IN THE MIDDLE; Grand Am replacement should be a player in midsize segment.(News)(Product/Service Evaluation)

Byline: ROGER HART

For Pontiac, the G6 is special. Because it will replace the General Motors division's high-volume-selling Grand Am, the G6 has got some big shoes to fill. The Grand Am started selling when Ronald Reagan was president in 1984, and nearly 4 million have been sold since.

The G6 rides on Pontiac's version of GM's solid Epsilon fwd midsize platform, which also underpins the Opel Vectra, Chevy Malibu and Malibu Maxx, and the new Saab 9-3.

Our initial test drive of pre-production G6s on two-lane roads in southern Michigan and at GM's Milford proving grounds found the car to boast no hint of chassis flex or vibration. The G6's 112.3-inch wheelbase is tops in the segment (to compare, the Mazda6 wheelbase measures 105.3 inches, the Honda Accord 107.9 and the Nissan Altima 110.2), and this is aimed to help with its ride quality, not to mention allowing for more interior space.

The suspension on these prototypes left us wanting greater refine- ment, however. With MacPherson struts in front and four-link independent with twin-tube shocks in the rear, the firm setup crashed over bumps, transmitting sharp sounds into the cabin; we would have appreciated a little less impact harshness. Also, for our tastes the variable-assist electric power steering felt too overboosted, leaving us with a numb feel for the road.

Initially, the G6 will be available in two models, designated G6 and G6 GT (base cars get 16-inch wheels, GT models get 17-inch wheels; GTs also get a stiffer suspension and trim upgrades). Both are powered by Pontiac's "all-new'' 3.5-liter 200-hp V6, but the engine's heritage is old school. The pushrod engine features a cast-iron block and aluminum head with two valves per cylinder. The engine makes 220 lb-ft of torque at 4400 revs, and while we have no problem with pushrod engines, the top competitors in this segment have smooth-revving overhead-cam powerplants. The dohc 3.5-liter ...