AP photo by Chris O'Meara / William Byron (24), Ross Chastain (42), and Garrett Smithley crash Thursday night at Daytona International Speedway during the second of two qualifying races for Sunday's Daytona 500.

DAYTONA BEACH, Fla. — What should have been a tune-up for the Daytona 500 might have cost Hendrick Motorsports the front row for the NASCAR Cup Series season opener.

Hendrick teammates Alex Bowman and William Byron were slated to lead the field to green in "The Great American Race," but that's in danger after Thursday night's qualifying events.

Bowman had an engine problem in the first of the two 150-mile races, and if his motor needs to be changed, he'll forfeit the pole position he earned Wednesday night. Byron was collected in a crash in the second of the Bluegreen Vacations Duels, and it ruined his Chevrolet. He has to move to a backup car for the 500, and the swap sends him to the back of the field.

"Bummer," Byron said. "Man the thing was fast."

Aric Almirola won the first race in the Stewart-Haas Racing No. 10 Ford. After a rain delay pushed the second race into a post-midnight finish, Austin Dillon used a crossover move in the Richard Childress Racing No. 3 Chevrolet to beat Bubba Wallace to the checkered flag.

Almirola is slated to start behind Byron but will slide up to the front row when Byron falls to the back. Dillon must wait to see if Hendrick changes Bowman's engine this weekend.

Austin Cindric and Kaz Grala both earned their first berths into the Daytona 500 by earning the two available transfer positions during Thursday's competition. Ty Dillon, Timmy Hill, Garrett Smithley and Noah Gragson all failed to advance.

Smithley and Gragson were racing each other for the transfer spot in the second race when Smithley tried to duck around Gragson. Brad Keselowski on his outside wasn't expecting Smithley to fill the gap and the two collided, starting a collision that eliminated both Smithley and Gragson. Byron also was caught in that crash.

Bowman sensed a problem with his engine, and rather than push it too far, he drove to pit road during the first race to give his No. 48 crew a chance to save his pole-winning run.

"I don't want to keep running it," Bowman said on the team radio.

The crew got his car back on track but must decide if it needs to make a preemptive engine change or gamble the one in the car now can go the distance Sunday. Winning the pole is prestigious, but actual starting position matters very little in a 500-mile race at a superspeedway.

"I feel like we did a good job understanding it, and hopefully we are able to diagnose it and make sure everything is good," crew chief Greg Ives said of the work ahead.

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AP photo by John Raoux / Crew members work on William Byron's car after he crashed Thursday night at Daytona International Speedway during a qualifying race for Sunday's Daytona 500, the season opener for the 2021 NASCAR Cup Series schedule.

Meanwhile, Wallace in his debut for the new 23XI Racing team owned by Michael Jordan and Joe Gibbs Racing driver Denny Hamlin flirted with his first win in a Cup Series car. He was the leader on the final lap of the second race until Dillon crossed to Wallace's inside and inched ahead.

Wallace tried to hold it steady in the No. 23 Toyota but wobbled after banging doors with Dillon.

"Good debut, but nothing to be really happy about myself," Wallace said. "It's OK for drivers to be hard on themselves — that's how we motivate ourselves. I know I've got a lot to learn here."

Cindric and Grala both got into their first Daytona 500 through NASCAR's quirky qualifying for its biggest race of the year. The race had 48 entrants for 40 slots, but all but four go to teams with guaranteed entry.

It pitted eight drivers for four spots, with two awarded to Ryan Preece and David Ragan in Wednesday's time trials. The other two spots were open to the highest-finishing "open" cars in each of Thursday's races — unless the highest finisher was Preece or Ragan.

Preece passed Ty Dillon in the final stretch of the first race, and even though Dillon finished sixth out of 22 cars, the transfer spot dropped to Cindric based on his qualifying speed from a day earlier.

"Some days it's your day, I guess," said Cindric, who found Dillon on pit road and shook his hand after the finish.

Grala's transfer was similar as Ragan was the highest-finishing open car in the second race, and Smithley and Gragson were part of the wreck that collected Byron.

Almirola won a Speedweeks race for the first time, and the Tampa Bay native noted its been a good week. It started with the Buccaneers winning the Super Bowl at their own stadium in Tampa, and Almirola thinks he's got a shot at winning NASCAR's big show on the opposite Florida coast this Sunday.

"This thing was a hot rod. Our race car is so fast," Almirola said. "We've got an incredible race car, and I can't wait for the Daytona 500."