The first two practice sessions for the Sprint Cup Series have been completed at Daytona International Speedway, and the top story of the day centers around a number of engine changes.

Hendrick Motorsports has changed engines in all four of its teams – including pole sitter Jimmie Johnson and Bud Shootout winner Dale Earnhardt Jr. However, the engine problems are not exclusively affecting just the Hendrick Motorsports teams.

Richard Childress Racing’s Clint Bowyer was also forced to swap engines, as well as the Haas CNC Racing teams of Scott Riggs and Jeremy Mayfield. Although Haas CNC Racing is an independent team, they lease their engines from Hendrick Motorsports.

As a result of these engine changes, these teams will be forced to go to the rear of their respective Gatorade Duel races tomorrow. Kyle Busch powered his new M&M’s Toyota Camry to the top of the speed charts in the first practice session. Busch was followed by Matt Kenseth, Scott Riggs, Carl Edwards and Busch’s Joe Gibbs Racing teammate Tony Stewart.

Ryan Newman’s Penske Racing Dodge led the field in the afternoon practice session. Newman was followed by two-time Daytona 500 champion Michael Waltrip, Dave Blaney, Bill Elliott and with Kasey Kahne rounding out the top-5.