Tony Stewart and Ryan Newman will have to start at the back of the field in Sunday's Kobalt Tools 500 at Atlanta Motor Speedway, after their Stewart-Haas team changed engines in their cars following Saturday's final practice session. Chevrolet officials said both the No. 14 and the No. 39 cars experienced valve train issues and chose to err on the side of caution and change engines.

Newman had qualified in the seventh position for today's race, while teammate Stewart was scheduled to start 15th.