The No. 13 Germain Racing Chevrolet of driver Ty Dillon and No. 00 StarCom Motorsports Racing Chevrolet of driver Landon Cassill both will start Sunday’s Monster Energy NASCAR Cup Series race at Las Vegas Motor Speedway (3:30 p.m. ET, FOX, PRN, SiriusXM NASCAR Radio) from the rear of the field following unapproved adjustments.

The No. 00 team changed a gear Sunday and the No. 13 team swapped in a new engine.

PHOTOS: Lineup, team rosters

Dillon had qualified 14th, his best starting position since the Texas spring race in 2017. Cassill qualified 31st. The drivers officially will “keep” their starting positions, but will roll to the back of the field on the warm-up laps.

This story will be updated if other cars are forced to start from the rear.