After claiming the fastest speed in the lone Sprint Cup practice at Auto Club Speedway, Austin Dillon put up an encore performance in the final Xfinity Series practice.
In the No. 2 Chevrolet, Austin Dillon recorded a speed of 176.622 mph while running 28 laps around the 2-mile track.
Kyle Busch, who was quickest in the first practice session, followed Dillon at 176.013 mph.
The top five was filled out by Ryan Blaney, Ty Dillon and Kyle Larson.
Qualifying for the Treatmyclot.com 300 will Saturday be at 12:15 p.m. ET on Fox Sports 1.