Pruett and his teammates could be the beneficiaries.
"The (car) is running really good," Pruett said. "It's fun to drive. The car is really fun. You can carve your way through traffic. You need to be heads-up, as we see out there. It can be a little wild with some of the GT cars. They'll get racing four or five abreast, and you really have to pick your way through those guys. Short of that, it's been trouble free."
Pruett gave way to longtime teammate Memo Rojas after 2½ hours behind the wheel. Rojas lost a spot on the driver change, but overtook Sebastien Bourdais around the three-hour mark. NASCAR driver Juan Pablo Montoya and IndyCar regular Charlie Kimball also drove stints in the No. 01 car.
Ganassi's other car, the No. 02, also spent considerable time near the front. But four-time IndyCar champion Dario Franchitti lost several positions on a restart that left him trying to make up spots as the sun set on the famed speedway. IndyCar's Scott Dixon, NASCAR's Jamie McMurray and sports-car specialist Joey Hand were teamed with Franchitti.
The star-studded field, which started with 57 cars split into three classes, included several NASCAR drivers and nearly a dozen IndyCar regulars.
Clint Bowyer, the runner-up in NASCAR's Sprint Cup Series last season, provided plenty of levity after his stint in the No. 56 Ferrari for AF Waltrip. Making his Rolex debut, Bowyer hit the kill switch getting into the GT car and drove through the chicane.
"My biggest worry being here is just staying out of the way and not ruining one of the DP cars," Bowyer said.
He also had concerns about the schedule.
"I don't know what you do now," he said. "I guess we have like a five-hour break. Twiddle our thumbs? What time is it anyway? 7:30? We're almost to halfway, right? Who came up with the idea of a 24-hour race anyway?"
Um, NASCAR founder Bill France Sr., which someone quickly pointed out.
"Oh, that's pretty cool then," Bowyer responded, drawing laughter.