The class structure of global sports car racing is constantly evolving. But the emergence and refinement of the FIA-homologated GT3 platform over nearly 20 years has stabilized production-based classes and created the opportunity for convergence between the IMSA WeatherTech SportsCar Championship, the FIA World Endurance Championship and many other series using GT3 race cars around the world.
The worldwide accessibility and appeal of GT3 has convinced Chevrolet and Ford to join the fray with factory-supported racing versions of the Corvette and Mustang. The Corvette Z06 GT3.R was revealed during 2023 Rolex 24 At Daytona festivities and has been in development with Corvette Racing partner team Pratt Miller Motorsports for the last year. Ford, meanwhile, unveiled the Mustang GT3 roughly six months later at the 100th anniversary celebration of the 24 Hours of Le Mans. Both cars will make their worldwide competition debut later this month in the 62nd Rolex 24.
Mustang and Corvette are joining a deep pool with nine other FIA-homologated GT3 cars that will compete in IMSA’s GTD and GTD PRO classes: Acura NSX Evo, Aston Martin Vantage, BMW M4, Ferrari 296, Lamborghini Huracán EVO2, Lexus RC F, McLaren 720S Evo, Mercedes-AMG and Porsche 911 (992).
Because the GT3 category emphasizes Pro-Am driver lineups, the cars are deliberately “user friendly,” with driver aids including traction control and antilock brakes. Through Balance of Performance adjustments, cars are designed to weigh between 1,200 and 1,300kg (2,645-2,866 pounds); power is regulated to 500 to 600hp and each car must meet specific drag-versus-downforce specifications.
Modern Corvettes and Mustangs require remarkably little modification to be transformed into racing cars. In fact, high-end production versions of both cars feature more powerful engines than their GT3 racing counterparts!
Like every Corvette, the GT3.R is built up from an aluminum chassis produced at Chevrolet’s Bowling Green Assembly plant in Kentucky. The 5.5-liter flat plane crankshaft DOHC V-8 engine — designated LT6 — also originates from the Performance Build Center in southern Kentucky. The racing version of the LT6 shares 70 percent of its components with the standard Z06 engine that originates on the same line. Pratt Miller then fabricates the integrated steel roll cage and side intrusion safety features.
As with the production Z06, the Corvette GT3.R utilizes double wishbone suspension, adding racing-specific springs, dampers and brake components. The racing car features a six-speed sequential transaxle rather than dual clutch eight-speed in the stock Z06.
