Six hours into the 50th Anniversary Grand Am Rolex 24 at Daytona, the action has been reminiscent of a sprint race, not North America’s longest endurance race.

For the fourth, fifth and sixth hours, a Who’s Who of international endurance racers sparred with stars of several other series at the head of the field. NASCAR and IndyCar star AJ Allmendinger, multiple Le Mans winner Allan McNish, IndyCar star Ryan Hunter-Reay, ALMS champs Joey Hand and Olly Gavin, and four-time IndyCar champion Dario Franchitti dueled for the lead; at the five-hour mark the top five cars were within five seconds of each other.

After the fifth full-course caution, five-and-a-half hours in, Alex Gurney in the #99 Gainsco Corvette-Riley and Olly Gavin in the #90 Corvette-Coyote moved to the front by not pitting. This pair lapped nose-to-tail, with Joey Hand in the #01 Telmex Ganassi Riley-BMW right on their tails. At the six-hour mark, six seconds separated the top five Daytona Prototypes.

Seven minutes later, Alex Gurney had to pit with a holed radiator, which sparked a battle for the lead which was won by Joey Hand, who pushed his way past Olly Gavin. Oz Neggri in the #60 Shank Riley-Ford forced his way past too. Gavin then headed for the pits, letting Michael McDowell in the #6 Shank car into third.

Moments later, the Oryx Audi R8, which was back on track after losing several hours in the pits changing the the clutch, went off again, spinning into a barrier, and bringing on the races sixth full-course caution. Several of the leaders pitted, guaranteeing another battle when the track went green again.

In GT, the Brumos and Magnus Porsches traded the lead with the Autohaus and Stevenson Camaros and the TRG and Alex Job Porsches. When the yellow flag waved at 9:37 p.m. the #57 Stevenson Camaro held the class lead, with five Porsches right behind him.

The #41 Dempsey racing lost one of its Mazdas to a collision, four hours in. The #41 RX-8 of Rick Johnson spun in traffic and was rammed hard in the front fender by a passing Porsche, then spun into a prototype. The Dempsey car had to retire.

Allan McNish in the #8 Starworks car spun the other Dempsey Mazda a little later, doing no damage. Five hours in the #18 and #19 Muehlner Motorsports Porsche spun seconds apart in unrelated incidents; the #19 collided with the #9 Action Express DP but both continued.

Seth Neiman in the #45 Flying Lizard Porsche slid into the #76 Krohn Lola Ford, and pitted but found no damage.

The #62 Risi Ferrari retired after five-and-a-half hours with a blown engine.