Somewhere in southeast Michigan, more than half of local businessman Roger Penske's massive car collection is hidden away at a secret location.

Indianapolis 500-winning cars, pace cars from those years, his championship-winning NASCAR stock cars and some of his personal collection sports cars — they're all cloaked in a bit of mystery.

But Penske gave The Detroit News a rare tour of the collection — the location remains a secret at his request — this week ahead of the Detroit Grand Prix.

“I love it here,” said Penske, admiring the "Penske Restoration," which he visits a few times a month. “It’s an amazing place.”

The billionaire businessman founded Penske Corporation, headquartered in Bloomfield Hills, brought the 2006 Super Bowl to Detroit, and has been an ambassador for the city. But at his core, the 82-year-old is a racer.

He has been since his father took him to the famed Indianapolis Motor Speedway as a spectator in 1951. He fell in love with racing that day and that has never waned. Penske was first a racer who had success in the early ‘60s before retiring in 1965 to concentrate on his business. He also became a team owner launching a racing organization against which all others are measured. Penske just celebrated his 50th year at the Indianapolis 500 and celebrated a half century in racing in 2016.

Strolling through Restoration is a walk through his vast history in racing, particularly Penske's dominance in IndyCar racing. Restoration was created in 1990 in California, then moved to Michigan International Speedway when Penske was the owner and then moved to this location in 2002.

Team Penske historian Bernie King has been with Penske for the last 37 years and helps restore the cars and maintains and organizes the collection that also includes boxes and boxes of photographs and team memorabilia, not to mention crates and crates of race car parts and engines.

King said there are 130 cars in the fleet, including the 75 at Restoration. Other cars are located at Penske’s museum and dealership in Scottsdale, Arizona, and at his Orange County, California, dealership; four are on loan to the Indianapolis Motor Speedway museum to commemorate this, his 50th year racing at the famed 2.5-mile oval; others are at his shops in North Carolina and at a few other museums around the country.

Restoration is a sensory overload, with eyes jumping from one historic Indy car to another. The facility is pristine and spotless, a Penske requirement at his businesses, race teams and shops, with the familiar Penske color scheme of red, black, gray and white on the walls.

Racing photographs loom large around the facility high on the walls, with one particular black and white attention-grabbing shot of Penske, racing the Zerex Special in 1962 with legendary racer Dan Gurney just behind.

“Isn’t that a great picture?” Penske said. “That’s a great picture with Gurney behind. There’s some good stuff here.”

King is currently working to restore Mark Donohue’s Indianapolis 500-winning car from 1972, Penske’s first Indy 500 victory as an owner. Four other race cars are parked at angles side by side, their paint schemes shining and dancing under the light: The one that four-time Indianapolis 500 winner Rick Mears won with in 1979 — his first win — his second in 1982, Mears’ pole-winning car from 1989, and Bobby Unser’s winning car from 1981.

Penske has won the Indianapolis 500 in every decade since the ‘70s, and that includes the gap from 1996-2000 when he and many other IndyCar regulars did not race there during the sport’s split. In another section of Restoration sit five Indy 500-winning cars: Al Unser Jr.’s from 1994, Sam Hornish’s from 2006, Gil DeFerran’s car from 2003 and Helio Castroneves’ cars from his wins in 2001 and 2002.

The goal is to keep the Indy 500 winning cars out of circulation after the race.

“We don’t want to run it if we can help it,” Penske said, saying they will take the cars to oval races, like Texas, just as a spare. “If we wrecked it, it wouldn’t be authentic.”

At the end of the season, the cars are shipped to the Team Penske shop in Mooresville, North Carolina.

“What we do is, we take the guys at the end of the season, people like Bernie who have worked on the cars all year, they take it completely down and put everything back,” Penske said. “They love doing it. Pagenaud’s car, we won’t race it again unless we need it as a spare. At the end of the season, we’ll be at the race shop at Mooresville, and they’ll take the car completely apart and rebuild it to 100 point, like it’s a brand-new car, and that goes in the museum. And we’ll have the pace car, too.”

The car Rochester Hills-native Brad Keselowski drove to the 2012 NASCAR Xfinity championship is there as well as a prized 1995 IROC car that was driven by Dale Earnhardt, who won the championship that year. Earnhardt didn’t drive for Penske, but he takes special pride in having a car driven by late legendary stock car champion.

“This is a perfect car. Isn’t that a great looking car?” Penske said. “This car is special. The fact that it’s Earnhardt … to have his IROC car is something.”

Penske has the pace cars driven those years, as well. There’s the 1988 Oldsmobile Quad 4, when Mears won his third Indy 500, and a 1979 Mustang from Mears’ first victory. The red Viper from 1991 when Mears won his fourth is especially slick, but Penske is partial to the Corvette with the red, white and blue paint scheme from 2006 when Hornish won.

“This is one of my favorites,” Penske said admiring the Corvette.

It is a popular car for fans to see.

“When we take it to a show, it’s a crowd pleaser,” King said.

All of the cars are fully functional so they can be transported as some appear in parades and race-enthusiast festivals. Often, King must bargain with engines or many of the car parts available if he needs a part for a car he is restoring. Not every car is on display at Restoration. Many are in bags that King explained protects them from moisture that can affect the magnesium on the aluminum.

It is hard to miss some of Penske’s personal cars in the midst of all his race cars. Among them, a Porsche 930 Turbo with manual boost that has only 3,500 miles and a spectacular Acura NSX.

"I drive them every once in a while," he said. To be noted, his personal car features the license plate: "1 Indy 17" which, of course, will be changed to 18.

Winning never gets old for Penske, who saw Pagenaud become his eighth driver to win the Indianapolis from the pole.

“We’ve got great drivers and when you think about it, at Indianapolis this year we had over 700 years of experience, if you aggregated everybody we had in our garage working on the cars,” Penske said. “That domain knowledge is so important and the consistency of the leadership with (Team Penske president Tim) Cindric and all the teams, that makes such a difference for us.”

Restoration documents Penske’s history in the sport, from the boxes of photographs organized by years, to the car blueprints and race programs to the actual cars. It is a place that holds special meaning for Penske, but his cars are like his kids, and he won’t single one out.

“I’ve been very careful not having a favorite,” he said, smiling. “Every one of them has a history. You think about the decades where we won the race. Every one of them is special. When you look at the cars and the guys that worked on them and evolution, it’s amazing."

And all of this is his. Only his.

“This is my collection of the Indy winners," Penske said, "because nobody in the world has 18 Indy winners and has 18 pace cars.”

achengelis@detroitnews.com

Twitter: @chengelis