-- Dale Earnhardt Jr.'s dominance at Daytona International Speedway roared on unabated today, as the driver won NASCAR's Koolerz 300 Grand National race, the final tune-up event for Sunday's Daytona 500.

It was Earnhardt's third victory on this 2.5-mile superspeedway in the last week, coming on the heels of his wins in the Bud Shootout and Twin 125-mile qualifying race. And it solidified his status as the favorite for Sunday's 500-miler.

"We've got a lot of be proud of, to be doing what we've done during Speedweeks," Earnhardt said. "But we know nothing equals up to that Daytona 500 victory."

If Earnhardt were to win his first Daytona 500 on Sunday, he would become the first driver in NASCAR history to sweep all four major events of a single Daytona "Speedweeks." Even his father, the late Dale Earnhardt, whose mastery on the track was unparalleled, never won more than three major NASCAR events during a single Speedweeks (in 1986, 1991 and 1993).

Making his debut in a Chevrolet that he co-owns with his stepmother, Teresa, Earnhardt vaulted into the lead of today's 300-mile race by taking only two fresh tires during a pit stop and was never seriously challenged after that, leading the final 67 laps of the 120-lap event.

The pit-stop exchange accounted for the only pass for the lead in the race, suggesting that Sunday's 500 may well be a tedious, single-file march to the finish -- at least among the front-runners.

There was plenty of dicing, scrambling and spinning farther back in the pack as drivers jockeyed for position at roughly 185 mph.

The last melee was triggered with two laps remaining when Todd Bodine intentionally rammed the bumper of Jimmy Vassar in an effort to push him through traffic. Vassar's Dodge lost control, however, and went spinning across traffic, ensnaring the cars of Scott Riggs, Mike McLaughlin and Jason Keller.

Keller's Ford burst into flames, bringing out the sixth caution of the race as smoke and debris spewed across the track. The event ended under caution, with Matt Kenseth (Ford) and Kevin Harvick (Chevy), who led the first 53 laps, finishing second and third.

Keller underwent a CT scan at nearby Halifax Medical Center and was released after being cleared of a possible concussion.

Even before today's race, Earnhardt and teammate Michael Waltrip were considered heavy favorites to win Sunday's 500, given their cars' muscle at NASCAR's restrictor-plate tracks. Despite rules that restrict horsepower at Daytona and Talladega Superspeedway, their Chevrolet engines just seem consistently stronger than other drivers'. They finished first and second, with Waltrip winning and Earnhardt following him across the line, in the 2001 Daytona 500.

"The 8 [Earnhardt] and 15 [Waltrip] have a secret figured out," conceded driver Rusty Wallace, who has never won the Daytona 500 in 20 attempts. "But I'm going to give 'em hell until the living end. If you can't outrun them, maybe you can outhandle them."

Security Beefed Up

With a crowd of 200,000 expected for Sunday's Daytona 500, security measures have been heightened around the speedway. Security guards are stopping all vehicles entering the infield to examine their undersides with mirrors. Air space over the track will be restricted during the race. The ranks of local fire fighters, police officers and paramedics have been stepped up. And rescue crews have been issued nerve agent antidote kits in case of a chemical attack.

Dale Earnhardt Jr. celebrates in victory lane after he captured Koolerz 300, his 3rd win at Daytona International Speedway in a week.