Dane Cameron has worked with Team Penske for years, so his engineers don’t need to hear much from him to know if his car is functioning properly.

“They know how to read me,” Cameron said. “They know when I’m happy or unhappy.”

What they read last week through his smile was encouraging. Two rival manufacturers — Porsche and Cadillac — met at Sebring International Raceway for testing of the cars that will debut next year as the Grand Touring Prototype (GTP) class in the IMSA WeatherTech SportsCar Championship.

Cameron, who tested the new Porsche 963 with fellow Porsche factory drivers Andre Lotterer, Felipe Nasr and Laurens Vanthoor, communicated an upbeat review. It’s been a complicated yet affirmative next step, he said about the first test of the car in North America, and uniquely important.

“It’s been pretty big so far,” Cameron said. “We have a ton of staff on hand and a ton of engineers supporting this program. Once everything is good and buttoned up, it’ll be more seamless, but the early running has been pretty intense, for sure.”

Similar responses were found at the other side of the Sebring paddock, where Earl Bamber, Sebastien Bourdais, Renger van der Zande and Alex Lynn tested the Cadillac LMDh prototype. Bamber gained a truer appreciation for the future of the class when he saw both prototypes up close — the first time that two GTP manufacturers shared the same track for a test.

“I think they look phenomenal,” Bamber said. “They’ve got fantastically different styling cues. You can definitely tell the difference between our Cadillac and the Porsche. You can definitely notice them on track. You have the different sounds as well.

“So, it’s not just where they all look the same. They’re definitely very, very different, and that’s what we need for this category as well. And I think it’s going to be fascinating.”

Cadillac and Porsche will jo in Acura and BMW when the WeatherTech Championship’s new top-level prototype class debuts in January in the Rolex 24 At Daytona, with Lamborghini set to join in 2024. The manufacturers are testing on their own now, with series-mandated testing for everyone scheduled following the 2022 season.

The significance of the GTP debut isn’t lost on anyone — especially the drivers.

“It’s going to be a golden era for motorsports in general with all the brands that are going to join,” Vanthoor said. “We haven’t seen it in more than 20 years. I hope it’s going to last long and makes it even better to be a part of it. Those who will win the big races in the championships, they will have won something really special.”

One of the more intriguing aspects of the Sebring test was the cooperation between the two participants. The LMDh cars being developed for the GTP class marry each manufacturer’s engine and bodywork styling to a shared hybrid platform. Engineers from Cadillac and Porsche exchanged data from the hybrid system, helping both manufacturers come to grips with its intricate personality.

“Two cars running is always better than one,” said Jonathan Diuguid, managing director of Porsche Penske Motorsport. “The manufacturers really bought into this shared hybrid platform, and it’s not developed just for our cars.

“It’s developed for Cadillac and all these other manufacturers that are joining the program. To see one of our manufacturer partners and competitors on the track at the same time is really exciting for everybody involved. We really welcome it. To be honest, we’ve been waiting for it for a long time.”

Waiting, in part, because the knowledge gained from racing translates to a brand’s production vehicles. The future of the automobile is electric, and the knowledge gained from racing in the new GTP class will go back into what the manufacturers sell in the showroom.

“It’s giving us a chance to move toward the future for automation, which is what we’re doing in our own company,” said Laura Wontrop Klauser, General Motors’ sports car program manager. “We’re transitioning to our electric future at General Motors. Any time you can use racing to help develop your production components, that’s great.

“Even though this is a hybrid system and not fully EV (electric vehicle), we’re still using an electric motor and we have a very intricate controlled system, which is all good learning that will go back to production.”

The initial feedback is quietly optimistic. A mountain remains to be climbed, but early steps through the foothills are promising. Just ask Cameron’s engineers.

“They know me, they trust me, they know what my feedback is and if I’m happy or unhappy,” Cameron said. “That’s just helping us make some strides even quicker.”