2013 Indy 500 results: Lead changes guarantee exciting final 100 laps

Though the frantic early pace slowed down in time, the 2013 Indianapolis 500 is still on course for a record number of lead changes as the race hits the halfway point. With 100 laps remaining, nine drivers have exchanged the lead 28 times -- just seven back of the record established a year ago.

The story thus far is AJ Allmendinger, who in his first Indy 500 start has driven to the front and currently leads Tony Kanaan and Ryan Hunter-Reay.

Allmendinger drove for Roger Penske last year in NASCAR, but a failed drug test in July led to his suspension and subsequent release from the team. However, with Penske needing a driver for this third IndyCar team, he elected to give Allmendinger a second chance and tabbed the former open-wheel pilot to fill the seat.

Allmendinger is seeking to give Penske his 17th Indy 500 victory. His teammates Helio Castroneves and Will Power run fourth and 10th, respectively.

Castroneves and Dario Franchitti are both seeking their fourth respective 500 wins, a feat only accomplished by A.J. Foyt, Al Unser Sr. and Rick Mears.

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