NEWTON, Iowa -- Helio Castroneves blistered the Iowa Speedway track record with a lap of 185.687 mph (17.3324 seconds) and led the 24-driver field in single-lap qualifying to determine the lineup for the three 50-lap Iowa Corn Indy 250 presented by DEKALB heat races (6:45 p.m. ET on indycar.com and the INDYCAR 36 app).

Scott Dixon held the single-lap qualifying record of 182.360 mph (17.6468 seconds) set June 23, 2007, in the first IZOD IndyCar Series race at the racetrack. Ryan Briscoe had the fastest lap at 184.005 mph (17.4908) set in the 2008 race.

The top six from the one timed trip on the .875-mile oval advanced directly to the third heat race. Joining Castroneves, the IZOD IndyCar Series championship points leader, will be Marco Andretti, Will Power, Tony Kanaan, James Hinchcliffe and Oriol Servia.

Click it: Single-lap qualifying results

Here's the heat race format, which adds the lure of bonus points – from nine points for the Verizon P1 Award winner and descending by one point each position to three points for seventh-eighth, two points for ninth and 10th and one point for 11th and 12th:

Race 1 -- Will consist of the even-numbered positions, starting with position 8 from single-car qualifying (Dixon). Others in the race: No. 14 Sato, No. 67 Newgarden, No. 98 Tagliani, No. 7 Bourdais, No. 6 Saavedra, No. 10 Franchitti, No. 1 Hunter-Reay and No. 18 Beatriz.

The results of Race 1 shall determine the even-numbered positions in the starting field, starting with position 12. The top two finishers will transfer to Race 3 and start in positions 8 and 10.

Race 2 -- Will consist of the odd-numbered positions, starting with position 7 from single-car qualifying (Ed Carpenter). Others in the race: No. 55 Vautier, No. 83 Kimball, No. 16 Jakes, No. 5 Viso, No. 77 Pagenaud, No. 15 Rahal, No. 19 Wilson, No. 78 De Silvestro

The results of Race 2 shall determine the odd-numbered positions in the starting field, starting with position 11. The top two finishers will transfer to Race 3 and start in positions 7 and 9.

Race 3 -- Will consist of positions 1 through 6 from single-car qualifying plus the first- and second-place finishers from Races 1 and 2 to determine the pole winner and the first five rows of the starting grid.

The 250-lap race will be broadcast by ABC (2:30 p.m. ET) June 23. It also will be available on IMS Radio Network affiliates, XM/Sirius 211, indycar.com (IMS Radio Network and Timing & Scoring) and INDYCAR 13 (in-car cameras, Timing & Scoring, IMS Radio Network). GET THE APP