Christopher Bell posted the fastest lap in the opening practice session Saturday at Gateway Motorsports Park with a lap of 136.030 mph.
He was followed by Noah Gragson (135.915 mph), Chase Briscoe (135.747), Todd Gilliland (135.595) and Justin Haley (135.294).
Toyota took three of the top four spots with Bell, Gragson and Gilliland.
The series has another practice today before qualifying and racing later this evening.