Larson, last season’s race winner at Sonoma (Calif.) Raceway, topped the Group B practice Saturday with an average lap speed of 90.423 mph.
Elliott – the current active Cup driver with the most road course wins – came in second in the same session at 90.194 mph.
The top six drivers in Group B all posted speeds faster than the fastest driver in Group A (A.J. Allmendinger).
Ross Chastain was third-fastest overall, Kyle Busch fourth and Daniel Suarez completed the top-five.
After two races utilizing the “Carousel” part of the course (Turns 4-7), NASCAR has returned to a previous version this season which is 1.99 miles long and contains a longer straightway.
Among those drivers who ran five or more consecutive laps, Elliott had the fastest average speed followed by Larson and Kyle Busch.
Group B
Track conditions clearly were better during the second 20-minute session as speeds picked up greatly.
Larson topped the session with an average lap of 90.423 mph with teammate Elliott close behind at 90.194 mph.
Chastain was third, Kyle Busch fourth and Suarez completed the top-five.
Group A
Allmendinger led the way in the first 20-minute session with an average lap speed of 89.898 mph.
“Being good for one lap and being good for a race is completely different,” he said. “I haven’t been here in four years so I’m trying to get used to the place again.”
Buescher was second-fastest (89.713 mph) and Harvick was third (89.685).
William Byron and Bubba Wallace rounded out the top-five in what ended up to be an uneventful session.