Saturday marks the start of the 2015 25 Hours of Thunderhill. The National Auto Sport Association race is held at Thunderhill Raceway Park in Willows, Calif.
The endurance race is comprised of teams with three to four drivers. Notable drivers in the field include two-time Indianapolis 500 winner Al Unser Jr. and NASCAR star Kurt Busch. Unser is competing for JFC Racing and Busch for RoadShagger Racing.
Other drivers of note: Ryan Eversley, Brian and Brad Frisselle, Alex Lloyd, Kyle Marcelli, Randy Pobst, Colin Braun, Joel Miller, Mike Skeen, Johannes van Overbeek, Guy Cosmo, Darren Law and Sean Rayhall.
The race gets underway Saturday at 11 am pacific time.