But in recent years, under the umbrella of Livonia-based Roush Enterprises, the Roush brand has come to mean much, much more.

Speedy wake board boats.

Seating systems for the Wizarding World of Harry Potter and other theme park rides around the world.

Self-driving Google car prototypes.

Airplanes, helicopters and military vehicles.

As a result, the Roush companies have doubled employment to more than 4,000 people over the past seven years – 3,000 of them in Michigan — and spread the Roush brand worldwide by activating marketing efforts in 19 countries.

“We feel like we’re the best kept secret here in southeast Michigan,” said Gary Jurick, president of Roush Performance group,  “and it’s really because of where we’ve been and where we’ve come from. Our services business is to be a silent partner for our customers and help them become successful.

“Because of that,” Jurick added during a recent interview, “we don’t talk much about what we do about who our customers are, and so it’s very easy to be behind the scenes and not be well-known.”

That’s how it was last year, when Google’s self-driving car group teamed up with Roush to develop and assemble pod-like prototypes at a nondescript Roush building in Livonia, before shipping them to California for further road testing.
“Google needed someone to deliver engineering excellence and also keep a secret,” Jurick said, “and we have a reputation for being able to keep quiet.”

When Chris Urmson, Google’s head of self-driving cars, talked to the press about Roush’s role in that project before a January speech in Detroit earlier this year, Roush Enterprises CEO Even Lyall was relieved to hear it. “I was really scared about it leaking,” Lyall told me last month at business event in Detroit, “because by that time we had a lot of other people and suppliers involved.”

The same reluctance to share details has shrouded the work of the Roush Entertainment unit with theme park customers including Disney and Universal Studios, dating back to 2007 when Universal was working work with vendors on the Harry Potter theme park in Orlando and subsequent projects in Japan, Singapore and Hollywood.

In a more recent diversification effort, Roush adapted the 6.2-liter 16-valve engine that powers F-150 SVT Raptor and F-Series Super Duty trucks for use in the water with a Supra wakeboard board made by Skier’s Choice.

At the SEMA show last month in Las Vegas, the Supra SE 550 Rush Edition Wake boat made its debut as the first-ever Roush-branded boat, boasting more than 500 horsepower and 575 pound-feet of torque.

The DNA running through all of the Roush corporate offshoots comes from founder and chairman Jack Roush, now 73, a former Ford engineer who competed in drag racing and sports car racing series beginning in the mid-1960s. In 1988 he founded a NASCAR  Sprint Cup team now called Roush Fenway racing, that he still runs today.

“Jack was always about speed, horsepower, making things faster,” said Don Manfredi, vice president marketing of Roush Performance.

That spirit runs through the Roush-branded custom Mustang sports cars and parts, which last year went global because Ford took the Mustang platform global. Roush Performance, which was selling the Mustang-related products in 2010 to only three countries — the U.S. Canada and Saudi Arabia – now has distribution in 19 countries and is preparing to target South Africa, South America and Mexico soon.

With that kind of expansion, Roush’s days as a best-kept secret appear to be numbered.