Blaney, driving the No. 12 Ford for Team Penske this week, put down a blistering lap of 182.834 mph to claim the opening practice.
Brennan Poole (182.642 mph) was the runner up and the top performing NXS regular.
Monster Energy NASCAR Cup Series drivers Denny Hamlin (181.977 mph), Brad Keselowski (181.910 mph), Austin Dillon (181.690 mph) and Kevin Harvick (181.568 mph) occupied positions three through six. Hamlin is the defending winner of the race.
In the second practice, Byron, a rookie, topped the charts with a speed of 182.716 mph.
Christopher Bell (182.008 mph), who is making his NXS debut this weekend in the Joe Gibbs Racing No. 18, finished the session in second place.
All 42 entries posted times in the first practice and only 37 of the entries completed a lap in the second practice.
Qualifying for the Hisense 4K TV 300 will be Saturday (May 27) at 10:05 a.m. ET on Fox Sports 1. The race is scheduled for later that day at 1 p.m. and will be broadcast on FS1 and MRN.
About the author
Michael Massie is a writer for Frontstretch. Massie, a Richmond, Va. native, has been a NASCAR superfan since childhood, when he frequented races at Richmond International Raceway. Massie is a lover of short track racing and travels around to the ones in his region. Outside of motorsports, the Virginia Tech grad can be seen cheering on his beloved Hokies.