Kyle Busch began his weekend at Pocono Raceway by posting the top speed in the first Cup practice session.
Busch recorded a top speed of 176.939 mph around the speedway. He made five laps in the session.
Busch was followed by Alex Bowman (175.490 mph), Clint Bowyer (175.486), Kyle Larson (175.452) and Kevin Harvick (175.278).
Kurt Busch was sixth fastest, giving Stewart-Haas Racing three cars in the top five.
Cole Custer, who is making his second Cup start, recorded the most laps with 19. He was 30th on the speed chart.