Updated

The rules are set, the classes — as cluttered as they may be — decided and the future of North American road racing is finally here.

Some 15 months after the merger of the Grand-AM and American Le Mans Series, the consolidated product will at last hit the track Saturday for the prestigious Rolex 24 at Daytona. The inaugural event for the TUDOR United SportsCar Championship will mark the first time sports cars in North America have been unified since 1997.

There are 67 cars across four classes scheduled to take the green flag for the twice-around-the-clock endurance race. While everyone is eager to see the unified series in action, even the most seasoned teams and drivers aren't sure what to expect.

"This sport is ready to put on a great show for a huge audience and we are very excited for what is next with the United SportsCar Championship," said Michael Shank, team owner of the 2012 winning team. "There are so many unknowns with the new rules and all the new classes, it is little bit like the first time for us."

Shank will be back with his 2012 winning lineup of Justin Wilson, racing for the first time since he was injured in the IndyCar season finale in October, AJ Allmendinger, John Pew and Oswaldo Negri Jr. in the Prototype (P) class. The class is comprised of the former Daytona Prototype class from Grand-AM, as well as the P2 class and the DeltaWing from ALMS.

The overall race winner will likely come from the P class, which also includes two entries from defending race winner Chip Ganassi Racing.

Ganassi has new faces for both of his lineups: He's paired Indy Lights champion and Rolex newcomer Sage Karam with Scott Pruett, Memo Rojas and Jamie McMurray. Pruett last year tied Hurley Haywood's mark of five overall Rolex victories and is looking for the record this year.

"There's something magical about Daytona, and I love coming to race in the Rolex 24," Pruett said. "Especially with the coming together of both series, it will be the best of the best."

The second Ganassi entry has an entirely new look as holdover Scott Dixon has three new teammates. Among them are Marino Franchitti, who slides into the spot once held by older brother, Dario, who was forced to retire from racing in November because of injuries suffered in an IndyCar crash at Houston. Also in the lineup is Indianapolis 500 winner Tony Kanaan, who got Franchitti's IndyCar seat with Ganassi, and Kyle Larson, who replaced Juan Pablo Montoya in Ganassi's NASCAR's side of the organization.

But Ganassi made an offseason switch to Ford and, like the Shank team, is using the new Ford EcoBoost turbo DP engines. Although powerful, reliability could be a question.

It makes the potential favorite Wayne Taylor's Velocity Worldwide Corvette entry, also from the P class. Taylor came out of a four-year retirement to join the lineup for a chance to drive with sons Ricky and Jordan, as well as longtime teammate Max Angelelli. The team finished second at the Rolex to Ganassi last season without Wayne Taylor, but Angelelli and Jordan Taylor won five races — including the final three of the season — to win the 2013 Grand-AM driver championship.

"When I stopped driving full-time back in 2006, I was done with driving and have been ever since," Wayne Taylor said. "Having said that, I knew that an opportunity to drive with my boys might never come again, so I really had to think hard about it. I'm a little nervous. In my career, I always was the guy who was the fastest. Now, I'm the slowest, so it's weird. My job is to stay out of trouble and stay on the lead lap."

The Taylors join the Andrettis, Leitzingers and Nonnamakers as a father sharing the same car with two sons in the Rolex 24.

The other three classes are the GT Le Mans (GTLM), Prototype Challenge (PC) and GT Daytona (GTD). The GTLM class and PC classes carry over in their entirety from ALMS. The GTD class combines the former Grand-AM Series GT, the ALMS GTC class and cars slightly modified from European GT3 competition.

Almost half of the 67-car field is the GT class, which features the Aston Martins, Audis, Ferraris and Porsches. The class includes defending race winner Alex Job Racing, which will be in a Porsche after winning in an Audi last year, Dempsey Racing, which features actor Patrick Dempsey and was fourth at the 24 Hours of Le Mans to just miss a podium finish.

Dempsey announced earlier this month he'll compete in the full United SportsCar season.

"I think I'm getting much more competitive, much more consistent lap times, a better understanding of traffic and a better understanding of how to talk to the engineers and express what I'm getting from the car," Dempsey said. "I'm improving the more seat time I get, with the more experience I get. So when I show up at the track, I know that I have a shot at winning if everything goes right."