Derrike Cope's doubters learned yesterday his Daytona 500 victory in February was no fluke.

Cope won that first career NASCAR Winston Cup race when leader Dale Earnhart cut a tire with a mile to go at Daytona. He won No. 2 yesterday in record fashion in the Budweiser 500 in Dover, Del., by taking charge and not letting go.

"From all the things that were said at Daytona it took a little bit of the sweetness away from it because a lot of people always said that I lucked into it," he said.

"But I feel like this win here says more to the world of auto racing that this team . . . is definitely a team that deserves to have some credibility in this sport. And that's all we're asking for."

Ken Schrader challenged Cope at the finish, steadily chopping away at Cope's 3.42-second lead with 30 miles to go. But Cope held him off in the battle of Chevrolets for a 1.3-second, $55,050 victory at an average speed of 123.993 mph, an event record on the high-banked, one-mile oval at Dover Downs International Speedway. Cale Yarborough's previous mark of 123.327 was set in May 1977. Pole sitter Dick Trickle finished third, followed by Mark Martin and Sterling Marlin. It was the 27th straight time the pole winner did not win at Dover.

Morgan Shepherd took the season-points lead away from Earnhardt with a sixth-place finish while Earnhardt spent most of the race in the garage and finished 31st.

A broken camshaft put Earnhardt's Chevrolet into the garage 22 laps into the race. He returned 240 laps and an hour, 45 minutes later, but he had engine problems again and was out on the 400th lap.

"If we gained any points at all, that's all that mattered," he said. "This track is a tough one to run all day. We gave it our best."

Earnhardt won twice at Dover last year, making Cope's win the third in a row for Chevrolet there.

Cope, who had not led a lap in nine races since Feb. 18 at Daytona, took his fourth lead of the day when he passed Rusty Wallace on the 446th of 500 laps.

As Wallace fell back, eventually finishing 10th, Schrader moved up.

"I thought I might have a chance to catch Derrike there at the end, but he was just too strong. He had us covered," Schrader said.

Shepherd is the only driver to finish in the top 10 in all 11 races so far in the 29-race schedule.

The Ford driver moved past Earnhardt into the season lead with 1,662 points. Earnhardt fell to third at 1,603 behind Martin's 1,630.

Miller 200: Al Unser Jr. earned his first oval track victory after Michael Andretti ran out of fuel while leading with less than two laps remaining in West Allis, Wis.

Unser trailed Andretti in the battle of second-generation Indy-car drivers by just over five seconds as the leaders drove the 199th lap on the one-mile Wisconsin State Fair Park track.

Suddenly, Andretti slowed and drove onto pit road as Unser's Chevrolet-powered Lola darted past and into the lead on the main straightaway.

Andretti pounded his steering wheel in frustration as his crew poured in enough fuel to allow him to finish the 200-mile race.

Unser, meanwhile, easily held off two-time defending race champion Rick Mears, beating him to the finish line by 0.73 seconds for his 10th career victory. He won $87,632.

"I could not have been luckier than I was today," Unser said. "For Michael to run out of gas, what can I say? It was just our day."

Unser, who added to his CART-PPG series point lead with his second victory in four starts this season, averaged 133.670 mph. That broke the race record of 130.160 by Mears last year.