Stewart-Haas cars to rear after engine changes

HAMPTON, Ga. -- Tony Stewart and Ryan Newman will start in the back of the field in Sunday's Kobalt Tools 500 at Atlanta Motor Speedway following engine changes in their primary cars after final practice Saturday.

Chevy officials said both the No. 14 and the No. 39 experienced valve train issues and chose to err on the side of caution and change engines.

Newman qualified in the seventh postion. Newman has failed to finish in two of the first three races this season, including an engine failure at Fontana. He's 32nd in points.

Stewart qualified 15th. He's coming off back-to-back top-10 finishes and is 11th in points.

Stewart and Newman will join Greg Biffle at the rear of the field. Biffle slapped the wall in final practice and was forced to a backup. He begins the race sixth in points.