On an unseasonably hot, humid day and night – even for Florida – the No. 5 Action Express Racing Mustang Sampling Corvette DP team remained cool and collected, taking the overall victory Saturday in the 63rd Mobil 1 Twelve Hours of Sebring Fueled by Fresh From Florida.

It was the first overall win for a Chevrolet in 50 years – since a Chevy-powered Chaparral won in 1965. Coincidentally, the Chaparral was the featured car at this year’s race, and that winning car was on hand.

The race began at 10:40 a.m., ended at 10:40 p.m., long enough for the brutal 3.74-mile road course to dash the dreams of many of the favorites in the 43-car field.

The Action Express Racing car, driven by Joao Barbosa, Christian Fittipaldi and Sebastien Bourdais, is a Prototype, the fastest of the four classes that race at Sebring. The team finished second in the 2015 TUDOR United SportsCar Championship season opener, the Rolex 24 At Daytona, and won the 2014 season championship. Just as impressive: Since the TUDOR Championship series began at Daytona in 2014, the Action Express team has finished every race, every lap, totaling 10,415 miles.

The team, led by former NASCAR crew chief Gary Nelson, prides itself in executing. “Always, we are trying to improve, no matter how well we do,” said Fittipaldi. “We learn to minimize mistakes, and that pays off at the end of the season.”

It was an all-Corvette podium, as second overall, and second in the Prototype class was the No. 10 Wayne Taylor Racing Konica Minolta Corvette DP, followed by the No. 90 VisitFlorida.com Corvette DP.

Finishing first in the Prototype Challenge (PC) class, and sixth overall, was the No. 52 car of PR1/Mathiasen Motorsports car driven by Mike Guasch, Andrew Palmer and Tom Kimber-Smith, which also won the class at Daytona. In second was the CORE autosport team, followed by the Performance Tech Motorsports team. The PC cars are essentially all the same, using ORECA chassis and Chevrolet V-8 engines. The winning team had a lot of confidence before the event: “We came in thinking, ‘This is our race to lose,” Guasch said.

The other two classes are based on production cars – the GT Le Mans (GTLM) class cars are slightly faster, and more expensive, than the GT Daytona (GTD) cars. And at the end, it appeared no one wanted to win the two classes, as the lead changed dramatically several times in the final few minutes.

GTLM is arguably the most hotly contested class, because the entries typically have the backing of manufacturers including Porsche, Chevrolet, BMW, Aston Martin and Ferrari.

At the checkered flag, a Chevrolet Corvette C7.R – a completely different car from the Prototype Corvettes -- earned bragging rights in GTLM with a win by the No. 3 car of Jan Magnussen, Antonio Garcia and Ryan Briscoe. A close second was the No. 62 Risi Ferrari 458 Italia, which also won the DEKRA Green Challenge award, given to the cleanest, fastest and most efficient car in the class. In third was the No. 17 Team Falken Tire Porsche 911 RSR.

“It was a massive fight every lap,” said Garcia.

“You couldn’t ask for a better start to the year,” Briscoe said. “We ran the first 36 hours of the season without a problem.”

GT Daytona (GTD) was the largest class with 14 starters, and taking the victory in the class was the Team Seattle/Alex Job Racing Porsche 911 GT America, driven by Ian James, Mario Farnbacher and Alex Riberas. An Alex Job Racing car lost a chance at a win last year due to an officiating error, so it was a sweet return to victory lane for the veteran owner on his home track.

Farnbacher drove the closing stint, and the Porsche was suffering from front brake problems. Near the end, he overshot a corner, drove into the dirt, and lost the lead. “I thought it was over,” he said. He was passed by the No. 33 Dodge Viper of Riley Motorsports – a car that burned to the ground in last year’s race, but was restored – and it led the class until the final five minutes, when it retired after overheating, giving the lead back to Farnbacher.

Finishing second was the No. 007 Aston-Martin Vantage of TRG-AMR, driven by Christina Nielsen, James Davison and Brandon Davis. Third was the No. 63 Scuderia Corse Ferrari 458 Italia. The No. 33 Dodge Viper of Riley Motorsports – a car that burned to the ground in last year’s race, but was restored – was leading the class until the final five minutes, when it retired after overheating, giving the lead back to Farnbacher..

Among those making an early exit was the second-fastest qualifier, the No. 1 Extreme Speed Tequila Patron Honda HPD ARX, which driver Ryan Dalziel drove to an early lead. Its sister car, the No. 2, started eighth and also retired early. The No. 1 had steering problems, the No. 2 lost engine turbo boost.

Also out early after a crash was the No. 60 Honda HPD Ligier JS P2 of Michael Shank Racing, which qualified fourth. Both Mazda SKYACTIV diesel Prototypes fell out long before the end, one with a broken drive belt, the other with overheating issues, as the cars finished 38th and 39th. The innovative DeltaWing had issues all day, until a broken suspension finally sent the team to the paddock for good.

There were multiple incidents during the race, but the scariest moment occurred on pit road, when two Prototype cars running side-by-side collided, sending one into Kevin Fox, a crewman for the No. 50 Fifty Plus Racing Riley BMW Prototype. Fox went flying, landing hard on the concrete, but was able to walk to the ambulance. He was evaluated and released at a Sebring hospital. Also making a quick trip to the track’s care center was Oliver Gavin, who crashed the No. 4 GTLM Chevrolet Corvette C7.R with about two hours to go. He was evaluated and released.

If you missed the Twelve Hours of Sebring, a two-hour highlights show will air Sunday morning from 8 to 10 a.m. on FOX Sports 1. The TUDOR Championship moves from Sebring to California for the third round of the series on April 18 for the Tequila Patron Sports Car Showcase at Long Beach.