 The following year, Custer began racing late models, winning ten races and earning Rookie of the Year honors.In 2013 Custer joined the K&N Pro Series East, making his debut at Bristol Motor Speedway for Ken Schrader Racing.During the season at Iowa Speedway, Custer won the pole position, led every lap, a record for a combination race, and won, becoming the youngest race winner in K&N Pro Series history at age 15, beating Dylan Kwasniewski's record by six months.