Carlos Castro Jr. is always in a hurry, and in fact, he couldn't even spare the time to savor his victory in the recent Long Island marathon.

"I told the emcee to hurry up and give me my trophy because I had to go back to work," said the 29-year-old Castro, who works as a groom for thoroughbred horse trainer Joe Orseno at Belmont Park. "I still had my running shorts on and my number stuck to me when my wife drove me back to Belmont. I changed on the way in, then I cleaned up my horse, Northface, put on his bandages and went with him to Aqueduct."

As part of his chores as a groom, Castro is responsible for making his horses look their best by brushing, bathing and rubbing them down. Apparently, Castro's winning ways rubbed off on Northface, who won last Sunday's seventh race by 13 lengths.

Castro actually gave himself plenty of time to get to work on Sunday, after he covered the 26.2 miles of the Long Island marathon in 2 hours, 37 minutes and 25 seconds. Even more amazing than running such a grueling race and heading right off to work is the fact that Castro ran in this marathon less than two weeks after running 112th in the Boston marathon. His time on Sunday was only 10 seconds off his Boston marathon time.

"Running two marathons that close together is not in the books," Castro said. "But I'm trying to write new books."

Castro's story is already different from that of most marathon runners. The Long Island marathon was only his fourth. His first was a seventh-place finish in this race last year. He then ran 169th in the New York City marathon last fall and then put in his most recent efforts, finally getting his first marathon victory.

"He came up a little short in Boston," Orseno joked. "So, I took over his training and had him ready to win in his last race."

Actually, Castro credits his friend David Lee, an exercise rider for Belmont Park trainer William "Red" Terrill with helping develop his talent, while Orseno gets credit for his patience and understanding.

"I can only do this because Joe Orseno and the rest of his staff have supported me," Castro said. "That's why I was so excited when Northface won on Sunday because all of us won.

"But David has been a special friend. He has no special training, but he runs and he reads a lot about health and about running and he is the one who kept telling me I could make it running marathons. I needed someone like him to believe in me to get me going."

The 48-year-old Lee is also a runner, whose time in the Boston marathon was 3:07. He said that the biggest challenge for Castro was harnessing his enthusiasm.

"Carlos has a lot of natural ability and he is not afraid to train on his own," Lee said. "He would run around the main track here at Belmont Park (a mile and a half) six or seven times and he was doing it in basketball shoes. But he would run too fast too soon. I couldn't train with him at first because he would just take off, where I was running more conservatively. When he started to run in the race, take off and then pull up in the middle is when he started conserving his energy.

"He has several people he looks to for advice besides me. He joined the Old Bethpage Runners' Club, and he runs in just about every race there is, marathon or not. He has made such a big improvement and he has an exceptional rate of recovery. That's why I felt he could win the Long Island marathon, even if he ran in Boston. He is easily one of the top three runners on Long Island and that is in any race: marathon, 5K or 10 K. I believe he wants to make the Olympic qualifying and he is training like an Olympian."

Castro, whose father had been a jockey in Puerto Rick and later an exercise rider in New York for owner Caesar Kimmel and trainer Jimmy Toner, grew up in East New York and met Monserrate while attending Forest Hills High School.

"Back in those days, I don't think a lot of people cared about running, at least not at my school," Castro said. "I went out for the track team and it was snowing that day. They made us shovel off the track, then we all ran the 400 meters. I beat everybody, and that was it. Looking back, I really think I needed someone to encourage me, to really get on me. I've always felt that they were just putting in time to get a paycheck.

"Angel would always encourage me, though. He kept telling me that if I kept running I would be on the cover of all these magazines. I ran, but I got involved in just hanging out around the neighborhood. I ran because I liked it, not because I felt I was going to do anything with it."

East New York is a rough part of the city, but Castro says he avoided the lure of drugs and street violence. He did, however, pick up a two-pack a day cigarette habit.

"It was crazy," he said. "Nick Caras (recreation director for the New York Racing Association at Belmont Park, Aqueduct and Saratoga) got me started in running 5K races. As soon as I would finish, I would grab a cigarette. But I feel lucky because that was really the only bad thing I ever did. Even when I was hanging out, the most I ever did was bang on garbage cans. I didn't do drugs and I never did anything that got me arrested. I guess smoking was stupid enough for me."

Castro managed to quit smoking, cold turkey, in a most surprising manner. It came while he was watching the Amateur Riders Club of America race at Aqueduct in late November, 1996.

"I was at home watching the races, and there was an amateur race at Aqueduct," Castro said. "I know the way certain people ride horses, and right away, I knew it was Angel (Monserrate). I hadn't seen Angel in a few years because he had been ruled off. But I was sure that was him. He had ridden races professionally before, and he didn't look like any of the amateur riders.

"Then, all of a sudden, they announce that the winning jockey is - Carlos Castro."

NYRA investigators quickly recognized Monserrate, who had been denied access to NYRA racetracks for several previous offenses. He was arrested, and later admitted that he had stolen credit cards and other identification off Castro and had used his friend's name in three previous amateur races around the country. His motivation, he said, was that he wanted to experience the thrill of riding and winning a race in New York.

"I reported all that stuff stolen a long time before that race," Castro said. "I couldn't believe Angel did that to me because we had been friends. Even now, I can't hold too much of a grudge because he was the first person to really have confidence in me.

"But I was disappointed in him, and I really didn't like my name being used the way it was. That day, and I mean exactly that day, I quit smoking and decided to make the most of my ability as a runner. I wanted to make a name for myself."

Castro follows an unconventional training schedule. He awakes at 4 a.m. daily, then heads from his home in Levittown to Belmont Park. As a rule, he is done by 2 p.m., and that's when the training starts.

"On Tuesdays, when we're not racing, I'll do speed work," he said. "I'll get with some of the elite runners of my running club, some of the faster runners. We'll job two miles to warm up, then we might run 10 four hundreds. Other days, I'll run anywhere from 10-18 miles, but right now, 13 miles for me is short. It's almost too easy."

Added Caras, "There are times when you say hello to Carlos and he says he has to run home. Then, you realize he actually means he has to run home."

With Belmont Park's 55-day spring/summer meet opening on Wednesday, May 13, Castro's workload is sure to increase. But he will continue to train hard and is even in the process of seeking sponsors to help further his career as a marathon runner.

"When I got done with the Boston marathon, I couldn't walk," Castro said. "All that downhill pounding really beat up my quadriceps and my Achilles tendons. But four days later, I felt like I hadn't even raced. David (Lee) is the one who encouraged me to try the Long Island marathon, and I felt pretty good after that.

"Naturally, when it comes to marathon running, you have to figure to beat the Kenyans. It is going to be tough, but after running in Boston and then coming back to win the Long Island marathon, I really believe I can do anything I put my mind to."

Castro will participate in the Floral Park Youth Council's 5K run at Belmont Park on Sunday, May 31 as part of the Belmont Stakes Festival. Additional information on the run may be obtained by calling 328-2753.

The Belmont Stakes Festival offers a wide variety of family activities throughout the metropolitan area in anticipation of the 130th running of the $1 million Belmont Stakes on Saturday, June 6. For information on the Belmont Stakes Festival, call 641-4700, ext. 574.