(FORTUNE Small Business) – Ken Walker's passion for vintage car racing has its roots in a 1950s teen-flick rite of passage. As a 16-year-old New Yorker spending the summer in California, Walker discovered the allure of Saturday night drag races. At that time Walker, a city kid, didn't even know how to drive. But once back East, he was eager to indulge his newfound need for speed. "I got my learner's permit at 17," says Walker. "By the time I was 18, it was revoked."

Now 61, he's been speeding, legally, for the past four decades. A vet-eran of the professional racing circuit, he's driven everything from 1975 Ferraris to Formula cars. As his earnings totaled a whopping $1,100, he knew enough not to quit his day job, pursuing a career as an architect while racing. Most recently, Walker founded Manhattan-based Retail Options, a strategic planning firm for early-stage retail companies.

In the mid-'90s, Walker switched from the fiercely competitive pro circuit to amateur vintage car racing. The low-key atmosphere and camaraderie, he says, suit him just fine. "People race to win, but basically we're there to have a good time." And spend money. His current ride, a 1964 Lotus Super 7, cost him $35,000. A single event can run $10,000, including maintenance, transportation costs, and a pit crew.

Walker has yet to report any major crashes on the vintage circuit. His most notable accident happened in 1979, when another car got too close to his. Their wheels locked, which sent his competitor's car sailing over his head. "I have one helmet at home with a tire tread across it," he says.

--Sasha Smith