2001 Roush Stage III Ford Mustang; The best-kept secret no longer.

Jack Roush's work for the Big Three has been one of Detroit's most closely guarded secrets. Finally, Roush's engineers get to go public. They're still not sharing any proprietary secrets, but they do get to show off some of their skills as they launch their 360-horsepower Stage III Mustang.

Let's play the word association game. I say, ``Jack Roush.'' You say... well, what you say depends on who you are and especially on what you do for a living.

If you are a motorsports fan, you recognize Jack Roush because of his racing teams-and because of his trademark straw hat. He's ``the cat in the hat,'' as Benny Parsons puts it, the cat whose cars dominated the SCCA's Trans-Am series and claimed 10 consecutive class victories in the 24 Hours of Daytona. But where Roush's name really has gain-ed national prominence is in NASCAR's Winston Cup series, with Mark Martin and Jeff Burton winning nearly 50 races in Roush-prepared Fords.

But if you work for the Big Three automakers, and especially if you are involved in product development, you know Jack Roush as Detroit's best-kept secret, and you're probably not allowed to respond in public when someone mentions his name. Nobody's supposed talk about how much work Roush Industries-with its 2000 employees in 50 locations in the United States, Mexico and England-does for the Big Three.

About all Roush's own company can say is that it does ``contract engineering, design, development, prototyping and pre-production projects for all of the Big Three automotive companies'' and that it also has electronics and other divisions that do everything from boundary element analysis (NVH control) to producing vibration dampers for hammers and computer hard drives and rebuilding Rolls-Royce Merlin motors for vintage aircraft.

Roush Racing is a huge operation with multiple cars in NASCAR's Winston Cup, Busch and Craftsman Truck series, and it builds engines for various customers (the Oldsmobile engines that won the Indianapolis 500 in two of the last four years were built by Roush). ``We also did a weight-reduction program for John Force... for his dragster, not for John,'' a Roush staffer confides.

Yet as big and as busy as Roush Racing may be, it accounts for only 30 percent of the Roush Industries' business. And most of that is top secret. Until now.