(FORTUNE Small Business) – Planes, Trains, and Automobiles—since childhood, Gary Briggs has loved anything with an engine in it. The son of an airline mechanic, Briggs spent 30 years managing corporate aviation facilities before he started Ascend Development, a Hayward, Calif., company that builds high-security hangars for private jets. In his spare time Briggs, 51, collects and restores classic sports cars from the 1950s, '60s, and '70s.

He didn't start out with such sleek machines. The first car he owned was a 1964 Buick Skylark, "which doesn't exactly set most people's hearts on fire," he says. But since then he's bought, restored, and sold more than 50 cars, and today he owns six in various stages of restoration. (His business comes in handy for storing the vehicles; Briggs rents space from his hangar customers when his three-car garage doesn't give him enough room.)

His current collection includes a 1973 Porsche 911 (his "everyday" car), a rare two-door 1975 Jaguar XJ12 coupe, a 1962 Ferrari 250 GTE that he's restoring with his father, and a 1967 Firebird convertible, which was his first restoration project. In November he'll be on the lookout for his next acquisition at the Palm Springs Exotic Car Auction, one of the largest such shows in California, where about 350 cars typically get sold to collectors and enthusiasts.

Restoring cars is pricey as hobbies go, but Briggs's collection is relatively affordable. Most of the models he buys are in the $5,000 to $15,000 range—a Porsche 911 from the 1960s or '70s, for example, can be had for $10,000 to $20,000—although he finds even better bargains on occasion. He once saw an ad in a community flier for a 1967 MG with an asking price of $99. It was literally buried under junk in the owner's garage and hadn't been driven in 20 years. Briggs unearthed the car, spent 20 hours restoring it, and sold it on eBay for $1,500.

Such makeovers aren't always profitable, though. With labor and parts, the cost of a detailed restoration can easily exceed a car's market value. Depending on the vehicle's needs, Briggs will perform both mechanical and aesthetic repairs, everything from overhauling the engine to cleaning every nut, bolt, and fastener. "You really have to enjoy it for the hobby aspect and not the money," he says.

Briggs's 1967 Firebird is a perfect example. "I shudder to think about the investment I have in that car," he says. After he bought it for $400 in 1984, Briggs spent 2,500 hours restoring it, including replacing the missing convertible-top frame, adding new upholstery and carpet, installing new door panels and shift linkage, detailing the engine compartment with factory hardware, and repainting the body in its original butternut-yellow finish. His 14-month-old daughter "helped" by picking up wrenches while Briggs worked under the car.

He sold the Firebird for $5,000 out of economic necessity, but his wife, knowing how hard it was for him to part with it, secretly kept the name and phone number of the buyer. A few months ago, when Briggs started talking about buying another car, she produced the slip of paper. Briggs traced the car to its current owner (who'd become so emotionally attached to the Firebird that she'd given it a name: Sunny). She initially refused to sell, but Briggs called her once a week until she caved in. This past July, Briggs bought his baby back for $12,000. He has no plans to name it—he's never been into naming cars—but don't let that fool you. "I'll never sell it," he says. "It's not a particularly valuable car, but it's got more value to me than anything else I have."