With the Ford-powered teams packing up early, Corvette DPs led the way in the third and final day of testing at the Roar Before the Rolex 24.

RESULTS: Combined Testing Results

A 1:39.748 lap time by the No. 90 Spirit of Daytona entry of Richard Westbrook was the quickest on Sunday but it was Christian Fittipaldi’s 1:38.630 lap in the No. 5 Action Express Racing Corvette DP, set in Friday’s opening session, that stood as the best of the weekend.

“It was a good test in most aspects but a little bit frustrating in others,” Fittipaldi said. “Instead of getting better, the car actually went the other way. But it is great to be on top of the time sheets.

“I am pretty sure everyone in the field is struggling right now with overall grip. All in all I think we have a solid team and a solid group of guys driving, so I am really excited to come back here for the 24 and try to win this thing.”

Corvette DPs swept the top four positions on Sunday, although it was the No. 01 Chip Ganassi Racing Riley-Ford that ended up third quickest of the weekend, thanks to Jamie McMurray’s 1:38.980 lap time on Saturday afternoon.

The five-time and defending Rolex 24 overall winners, however, didn’t take part in any further sessions after developing header issues on its new Ford EcoBoost engines. Fellow Ford-powered squad Michael Shank Racing also packed up early.

The much-talked about Prototype Balance of Performance ended with the quickest P2 car within 1.2 seconds of the pace-setting DP.

Ryan Dalziel peddled the No. 01 Extreme Speed Motorsports HPD ARX-03b to a best lap of 1:39.750, which was set on Saturday morning. The Scot’s time was more than a half-second quicker than OAK Racing’s Morgan-Nissan, which ended up 10th quickest overall and the second-best P2 car.

Of note, the DeltaWing posted a respectable 1:40.508 lap time to go 11th quickest, ahead of the debuting No. 6 Muscle Milk Pickett Racing Oreca 03 Nissan, which was running to a smaller, ACO-sized air restrictor.

Nick Tandy’s quick time set on Friday stood as the best of the weekend in GTLM, putting Porsche North America’s new factory program atop the time sheets in the competitive production-based ranks.

The Englishman peddled the No. 911 entry to a best lap of 1:45.564, which ended up two-tenths quicker than the pair of factory Corvette C7.Rs, which were second and third quickest in class.

More than 100 laps were completed by the two new CORE autosport-operated Porsche 911 RSRs, which are making their North American full-season debut this year.

“It was nice to be at the top of the time sheets, as that’s everywhere wants to be,” Tandy said on Friday. “With the tire war and the job Michelin had done, not just with Porsche but many of the other manufacturers as well, our cars are very good with mechanical grip.

“It’s going to be very interesting when we get racing, that’s for sure.”

The No. 91 SRT Motorsports Viper GTS-R was fourth on the GTLM time sheets, followed by the No. 97 Aston Martin Vantage V8, which plans to contest the four-round Tequila Patron North American Endurance Cup this year.

Starworks Motorsport led the way in Prototype Challenge, with a 1:42.010 lap time by Sam Bird, in his sports car racing debut, ending up the quickest of the class.

The GP2 runner-up outpaced class veterans Colin Braun (CORE autosport) and Tom Kimber-Smith (8Star Motorsports), who were second and third quickest of the weekend in their Oreca FLM09 cars.

The new-for-2014 GT Daytona class saw Flying Lizard Motorsports lead the pack, with Spencer Pumpelly peddling the No. 45 Audi R8 LMS to a 1:47.981 lap time.

All three of the car’s co-drivers: Pumpelly, Nelson Canache and Markus Winkelhock, topped the time charts at one point during the weekend.

“We left the test here in November, not everyone was really happy, so the guys did a lot of work and came back with a much better car,” Pumpelly said.

“We’re narrowing in on where it likes to run and I think after the test, we made a good amount of progress and were at the front of the field in most of the sessions. So I’m pretty confident.”

The Lizard’s Audi was nearly three-tenths clear of the competition, with the No. 58 Snow Racing Porsche 911 GT America and No. 71 Park Place Motorsports Porsche completing the top-three in class.

A total of 62 cars turned laps over the course of the weekend, which surprisingly saw only a few significant accidents.

The No. 2 ESM HPD of Johannes van Overbeek crashed at the Bus Stop chicane on Sunday morning and did not return to the track.

There were other incidents for the No. 54 CORE autosport Oreca FLM09, No. 58 Snow Racing Porsche and No. 18 Performance Tech Oreca, also on Sunday.