Austin Dillon, winner of three poles in the Camping World Truck Series this season, put himself in position to notch a fourth by leading Thursday night's opening practice for the EnjoyIllinois.com 225 at Chicagoland Speedway.

Dillon, having an impressive rookie season in the Richard Childress Racing No. 3 truck, topped the evening practice with a speed of 173.555 mph.

Kyle Busch, a Sprint Cup regular who has been successful with sporadic invasions into the Truck series this year, was second at 173.260.

Dillon and Busch were the only drivers above the 173 mark.

Following in the top five were Ron Hornaday Jr., Todd Bodine and Aric Almirola.

Bodine, three times a winner this season, has a commanding 211-point lead in the series standings. Almirola is second.

Another practice round, qualifying and the race are scheduled Friday.