New rear end helps Pontiacs get even

While chasing Tony Stewart's Pontiac Grand Prix in the final laps of the rain-shortened NASCAR race at Michigan Speedway in Brooklyn this month, Chevrolet driver Dale Earnhardt got an up-close look at the Grand Prix's redesigned rear end.

At more than 180 mph, Earnhardt, who finished second behind Stewart, probably couldn't discern the subtle changes NASCAR officials permitted the Pontiac teams to make to their rear bumper covers. But they were indeed there: The new bumper cover is higher and wider and gives the Grand Prix an additional 90 to 100 pounds (7 percent) of downforce, bringing it up to par with those on the Monte Carlos and the Ford Taurus. Downforce helps hold the car on the track and increases a car's speed.

Pontiac hopes the bumper change can help propel it to its first Winston Cup championship since 1989.

Some Chevy and Ford teams griped behind closed doors about NASCAR's decision to allow Pontiac to restyle the bumpers; they apparently feel the Pontiacs need no assistance. After 14 races this season, Pontiac drivers are first (Bobby Labonte) and third (Ward Burton) in the Winston Cup championship standings, and Labonte's teammate, Stewart, is a two-time winner.

''A lot of the argument we've heard from the competitors is that we are too good already,'' said Jimmy Makar, Labonte's crew chief. ''But I say that's not a valid argument. I think the gap between us and the other teams is due to our team finding other ways to run up front.''

NASCAR officials insist they amended the rules not to aid Pontiac but to create a level playing field. In fact, the rule change is the second since the season started. In March, NASCAR officials allowed the Chevrolet teams to extend their front air dams by two inches, increasing the Monte Carlo's front end downforce.

Pontiac's downforce handicap was detected in March during wind tunnel comparisons of the Pontiac, Chevy and Ford aerodynamics. NASCAR concluded the Grand Prix to be at a disadvantage to the Monte Carlo and Taurus, with a deficit of 180 pounds of downforce, most of that in the rear of the car.