A Daytona Prototype ended up fastest on the first day of this week's official United SportsCar Championship test at Sebring.
Sebastien Bourdais topped the Thursday times aboard the Daytona 24 Hours-winning Action Express Coyote-Chevrolet Corvette DP.
The Frenchman's time of 1m52.480s in the afternoon put him 0.7s ahead of the OAK Racing's LMP2 Morgan-Nissan driven by Gustavo Yacaman, who set his fastest time in the morning session.
Data gathered over the course of the two-day test, which finishes today, will be used to determine the Adjustment of Performance between the DPs and P2s in the Prototype class.
The DPs are running with the rear diffusers that were removed from the cars in the wake of two aerial incidents in testing at Daytona in November.
The P2s are running in high-downforce configuration at Sebring rather than with the Le Mans bodywork in which they had to use at Daytona, but are running at the same 900kg minimum weight as at the USC opener.
Bourdais, who will again share the lead Action Express car with Joao Barbosa and Christian Fittipaldi in next month's Sebring 12 Hours, said: "We're still trying to sort through the balance and the new aero configuration.
"We just kind of nailed it and were able to put down a really good lap at the end of the session."
The Spirit of Daytona Coyote, shared by Richard Westbrook and Michael Valiante, was third fastest ahead of the Wayne Taylor Racing Dallara-Chevrolet Corvette DP.
The GT Le Mans class was led by the factory CORE Autosport team's pair of Porsche 911 RSRs.
Jorg Bergmeister set the fastest lap of the day in the morning session with a 2m00.048s, which was just three tenths faster than team-mate Patrick Pilet's afternoon best.
Eight cars representing five manufacturers were separated by less than one second over the course of the two session.
Marc Goossens was third fastest in the best of Chrysler's SRT Viper GTS-Rs, despite the V10-powered machines being hit by a 15kg weight penalty and being given a smaller-diameter engine air-restrictor ahead of the test.
The PC class for the one-make ORECA-Chevrolet FLM09 was led by the 8Star entry driven by Tom Kimber-Smith, while Dane Cameron was fastest in GT Daytona in Turner Motorsports BMW Z4.