Practice Results: NASCAR Cup Cook Out Southern 500 at Darlington

Originally posted on Racing America on SI
By Toby Christie | Last updated Aug 30, 2025 10:11 AM ET

Lesley Ann Miller, Lumen Digital Agency for Toyota GAZOO Racing

Michael McDowell led the way in single-lap speed in Saturday's NASCAR Cup Series practice session for Sunday's Cook Out Southern 500 at Darlington Raceway. However, the track conditions in Group 1's practice seemed to be more condusive to faster lap times than Group 2, which featured the 16 NASCAR Cup Series Playoff drivers.

Bubba Wallace was the fastest Playoff driver in single-lap speed as he ranked eighth in the practice session.

Ryan Preece was the first driver to acquire a Darlington Stripe this weekend as he scrubbed the wall with his No. 60 RFK Racing Ford Mustang early in Group 1 practice on Saturday.

Stripe. pic.twitter.com/fEGhpqeFan
— NASCAR (@NASCAR) August 30, 2025

Zane Smith experienced a spin in Group 1, while attempting to practice a green flag pit entrance.

Additionally, regular-season champion William Byron nearly experienced disaster as he had to aggressively slow in the opening moments of practice in order not to make contact with Chris Buescher, who had turned hard right to get around Josh Berry. Byron would go on to turn the third-fastest overall lap among the 16 Playoff drivers, as he ranked 16th in the session.

William Byron and the No. 24 Hendrick team nearly experienced a disastrous start to the weekend. Heads up driving to get slowed in time for this. pic.twitter.com/g8mRWJan5M
— Toby Christie (@Toby_Christie) August 30, 2025