Last October, Bob Vaughan left a $70,000-a-year job in real estate to manage the career of a college dropout who became a jockey on the advice of a stranger he met in a shopping mall.

Vaughan received no strange looks from his coworkers, no harsh words from his wife. They supported the switch, recognizing his desire to rejoin the sport that had commanded his attention for 25 years.

In his second stint as a jockey's agent, Vaughan now owns the rights to Allen Stacy, who, with little understudy, has become the nation's leading apprentice jockey with 33 victories this year.

Vaughan's return to racing was a calculated gamble, Stacy's introduction to the sport a fluke. Stacy still might be headed for a physical education degree at Longwood College in Virginia had he not been Christmas shopping in his hometown of Midlothian, Va., one day in 1983.

Said Stacy, "Me and a friend were walking through a mall. Out of nowhere, this guy came up to me and asked me if I'd try on a shirt for his grandson, who was 8 years old. Of course, I was 18.

"I had no idea who he was. He asked if I rode horses, and I said no. Before too long, that's just about all I was doing."

The stranger was George Andrews, who raised thoroughbreds at Rockets Hill Farm in Ashland, Va., before retiring to Arizona. He developed yearling colts and 2-year-old fillies and, in this case, an 18-year-old jockey. Stacy withdrew from Longwood after his freshman year and went to work for Andrews.

"I'd ridden horses before, just for recreation," Stacy said. "I've always loved animals, but I never really had a chance to work with them. I decided to try riding full-time. In this business, there isn't time for much else."

Most jockeys spend years preparing for races. Stacy needed 14 months, refining his skills under trainer Eddie Gaudet. His first race was last Aug. 8.

"When I first got him, he was very green but very athletic," Gaudet said. "Physically, there was no question about his potential. It was a matter of how well he was going to discipline himself.

"But right from the start, he was all business and very, very quick to learn. He studied balance. He carried a stick around with him in the mornings, switching hands with it. He tried to patent everything before he went out and executed it."

Stacy, 20, is 5-foot-1 and weighs almost 105 pounds. He has a muscular, wedge-shaped body with veins that bulge from bicep to shoulder. His handshake, like his determination, is strong and unrelenting.

"I've always done pretty well in all sports where size doesn't matter," he said.

He was a wrestler at Longwood and, before that, a gymnast. The experience helped ease the transition to riding.

"In wrestling, riding a person was, in fact, one of my better skills," Stacy said. "You've got to stay with your opponent all the time. In (race) riding, it's the same principle. You've got to control your horse, especially coming out of the gate.

"In gymnastics, you learn balance, and that really helps when you're riding. A couple of times when I've gone down, I think I've had a great advantage. I knew where I was the whole time because of my training in gymnastics. You learn how to fall."

The spills didn't thwart his swift ascent through Laurel's jockey standings, in which he ranks fourth with 65 victories (since September). He has justified Vaughan's abrupt career change.

"I wanted a young apprentice rider, someone I could start with fresh and help develop," Vaughan said. "What more could I ask for? I feel like I've got a rough diamond. He's gonna shine."

As an agent for Stacy and Danny Nied, Vaughan receives 25 percent of the jockeys' earnings. Vaughan said he anticipates 1986 income of between $70,000 and $100,000. "Money is not the main priority here, at least not now," he said. "I see a chance for this kid to do something big. He's got a helluva future."

A successful jockey agent is part handicapper, part salesman, part publicist, and Vaughan seems to have mastered the synthesis. He arranges Stacy's riding assignments; if Stacy is named on more than one horse in a race, Vaughan selects the mount.

The control doesn't end there. Vaughan has prepared a grueling schedule for Stacy, when the jockey will ride at Pimlico (which opens Feb. 17) by day and at Garden State by night to pursue Chris McCarron's 11-year-old record of 546 victories by an apprentice. Stacy needs 513 to tie.

Vaughan said he has arranged to rent a twinengine, six-seat plane -- at $135 an hour. If it's not available, they'll drive or take the train.

"I believe he can do it with all my heart and soul," Vaughan said. "I'm not a dreamer, I'm a realist. If I didn't think I had a kid with endurance, I wouldn't even think of it. But he's so strong and fit, and I know how to keep him healthy."

Garden State's meeting lasts 90 days. While Stacy has the resolve, he is lacking Vaughan's exuberance.

"Being the best (apprentice) in the country doesn't excite me really," said Stacy, who retains his apprenticeship until November. "I'm the type that records don't mean a whole lot to. It's tough to say what I'm motivated by. I like playing the game. I like talking to horses; I think they respond. I even do stupid things like sing to them.

"I just love to race ride. Riding day and night is a challenge to me more than anything else."

Stacy's name is getting around. He has ridden in New York after receiving offers from such prominent trainers as Butch Lenzini, Mike Sedlacek and Bobby Lake. New York offers greater exposure and more lucrative purses than Maryland, leaving Stacy and Vaughan with a decision.

"If we can get five or six trainers to say, 'We'll ride you,' then maybe we'll think about going there (permanently)," Stacy said. "But it's not in our immediate plans."

"My home and my family is here, and Allen's family is in Richmond," Vaughan said. "We realize that New York is the place to be. But what kind of price do you put on happiness?"