Crews work on cars after practice for the NASCAR Sprint Cup Series Jeff Byrd 500 race at Bristol Motor Speedway Friday, March 18, 2011 in Bristol, Tenn. (AP Photo/Wade Payne)

Photo by: WADE PAYNE

Crews work on cars after practice for the NASCAR Sprint Cup Series Jeff Byrd 500 race at Bristol Motor Speedway Friday, March 18, 2011 in Bristol, Tenn. (AP Photo/Wade Payne)