Hendrick Motorsports led the way for the majority of Saturday's first practice, but a new name arrived at the top of the board in the closing moments.
Jimmie Johnson set the pace early in the session at 178.861mph, just ahead of young teammate
Alex Bowman at 178.749mph.
But in the final seconds of the 50 minute practice, Team Penske
Ryan Blaney rocketed to the top of the charts on his 14th lap, putting up a 178.992mph lap.
Johnson also ran the most laps at 31, telling NBCSN afterwards, "really impressed with the way we unloaded and how this Chevrolet is driving."
Chase Elliott, Daniel Suarez, Ryan Newman, Denny Hamlin,
Kyle Larson, Joey Logano, and Jamie McMurray rounded out the top-ten.
Defending race winner Martin Truex Jr. was down in 19th on the speed charts.
The session went incident-free. Two drivers -- Landon Cassill and B.J. McLeod -- were given 15-minute practice holds for being late to inspection.