Cadillac Whelen and Corvette Racing remain the teams to beat in practice for the IMSA Chevrolet Sports Car Classic in Detroit, to the delight of the GM representatives in front of their worldwide headquarters.

On-track action at the Chevrolet Detroit Grand Prix kicked off with the first IMSA WeatherTech SportsCar Championship free practice session of the day, with GM cars leading both classes in the first 90-minute session.

The third quarter of the Mobil 1 Twelve Hours of Sebring ended under the race's ninth caution after Fred Makowiecki in the No. 6 Porsche Penske Motorsports 963 made contact with the GTD-class No. 66 Gradient Racing Acura NSX GT3 Evo22 while attempting to pass in Turn 17. The Acura...