Ambrose will join AJ Allmendinger, Justin Wilson, John Pew and Ozz Negri. The Australian tested with the team last week at Daytona while Negri is recovering from an offseason injury.
The team led the Daytona Prototype class in five of eight practice sessions during testing.
Team owner Shank said Ambrose gelled quickly with the team, was fast in the car and will be a tremendous supplement to the lineup in the biggest race of the year for the organization. The lineup of NASCAR driver Allmendinger, IndyCar driver Wilson and regular Grand-Am drivers Pew and Negri scored the win last season for Shank.