RELATED: Practice results | Full schedule for PoconoKyle Larson soared atop the Monster Energy NASCAR Cup Series leaderboard in Friday’s opening practice at Pocono Raceway.Larson, the hard-luck runner-up last weekend at Dover, clocked a lap of 177.312 mph in the Chip Ganassi Racing No. 42 Chevrolet around the 2.5-mile track. The 85-minute session was the opening tune-up for Sunday’s Axalta presents the Pocono 400 (3 p.m. ET, FS1, MRN, SiriusXM NASCAR Radio).Kyle Busch was second-fastest at 177.235 mph in the Joe Gibbs Racing No. 18 Toyota. Sunday’s 400 will mark the first race of the season for interim crew chief Ben Beshore, who will stand in for Adam Stevens, serving a four-race suspension for a violation last weekend at Dover.RELATED: Learn more about the No. 18 crew chiefMatt Kenseth, Kevin Harvick and Joey Logano completed the top five on the speed chart.Darrell Wallace Jr., scheduled to make his premier-series debut in the Richard Petty Motorsports No. 43 Ford, was 19th-fastest. Wallace was named earlier in the week as the interim replacement for Aric Almirola, who is recovering from a broken back suffered in a May 13 crash at Kansas Speedway.“I’m trying to figure these cars out. It’s a lot of fun and a very cool opportunity,” said Wallace, who will pull double-duty at Pocono with participation in Saturday’s XFINITY Series race. “At the same time, we’re hoping Aric gets back very quick and heals up 100 percent, but in the meantime, I’m going to try to do the best I can for you, bud. This is a lot of fun, a very cool experience. I’m driving a Cup car — it’s awesome.”Dale Earnhardt Jr. ran into early trouble in opening practice, over-revving his engine after just eight laps. His Hendrick Motorsports No. 88 Chevrolet — 29th-fastest in the opening session — will start at the rear of the 39-car field in Sunday’s 400-miler after his team made an engine change.MORE: Earnhardt Jr. to the rear of the fieldSeries points leader Martin Truex Jr. was 12th-fastest, making only limited participation in opening practice. His Furniture Row Racing No. 78 Toyota spent extra time in the garage as the team dealt with a steering issue.Jimmie Johnson, last week’s victor at Dover and a three-time winner this season, posted the 10th-fastest lap (175.271 mph) in the Hendrick Motorsports No. 48 Chevrolet. Kurt Busch, a winner in this race last season, was 15th-fastest in the Stewart-Haas Racing No. 41 Ford.