For final practice at Iowa Speedway for the Iowa Corn 600 seven Chevrolet and three Hondas would be in the top-10.
The fastest speed was 179.103 mph posted by Tony Kanaan, driver of the No. 10 NTT Data Chevrolet. Josef Newgarden, driver of the No. 21 Fuzzy’s Chevrolet was in second with a speed of 178.610 mph. Third and fourth went to Team Penkse teammates, Simon Pagenaud, driver of the No. 22 Menards Chevrolet, with a speed of 178.392 mph, and Helio Castroneves, driver of the No. 3 Hitachi Chevrolet with a speed of 178.372 mph.
Rounding out the top-five was James Hinchcliffe, driver of the No. 5 Arrow Electric Honda, with a speed of 178.372 mph, the fastest Honda of the session.
Sixth through tenth were as follows. Mikhail Aleshin, Sebastien Bourdais, Will Power, Graham Rahal and Charlie Kimball.