ELKHART LAKE, Wis. – official release — When the IMSA Continental Tire SportsCar Challenge field gets the green flag at Road America on Saturday, it will be the debut professional race for 16-year-old Britt Casey Jr. Casey will be co-driving the No. 27 Freedom Autosport Mazda MX-5 with Mark White. Most recently, Casey finished second in the Spec Miata Cup …