Barcelona ’92 OLYMPICS / DAY 13 : It’s a Field Day for U.S. Track : Track and field: Young breaks Moses’ record in 400 hurdles. Marsh, Torrence and Lewis also win gold. Devers stumbles at finish.

Excluding the boycotted Games of 1984, when even Sam the Eagle probably could have won an event or two, the United States had one of its best days ever in track and field Thursday at the Summer Olympics.

In six events: Nine medals, including four golds.

It was also one of those days when the U.S. Olympic Committee is glad that California--Southern California in particular--does not follow the lead of the former Soviet and Yugoslav republics that have seceded from their unions.

Four of Thursday’s medalists are from the Southland, including three from UCLA.

One of the former Bruins, Kevin Young of Los Angeles, not only won his event, the 400-meter intermediate hurdles, he eclipsed the nine-year-old world record previously held by Edwin Moses of Newport Beach. Moses’ record was 47.02 seconds. Young won in 46.78.

Other winners were 200-meter sprinters Mike Marsh of Los Angeles and Gwen Torrence of Decatur, Ga., and long jumper Carl Lewis of Houston.

Marsh, another former Bruin, came within one-hundredth of a second in Wednesday’s semifinals of equaling the oldest existing track and field record, the 19.72 seconds for the 200 by Italy’s Pietro Mennea in 1979.

Marsh was not as fast in the final, 20.01, but he has the gold medal. Michael Bates, a Seattle Seahawk draft choice from Tucson, got the bronze. He was third in 20.38.

Torrence won her race in 21.81, then stirred an ill wind by continuing her assault on anonymous drug users in a bizarre news conference.

Lewis won his seventh gold medal in four events since 1984 with a long--but not too long--jump of 28 feet 5 1/2 inches. He had hoped that the world record-holder, Mike Powell of Alta Loma and UCLA, would push him to the first 30-foot jump.

But Powell could not find the “pop” that enabled him to break Lewis’ 65-meet winning streak and Bob Beamon’s 23-year-old world record last summer, finishing second at 28-4 1/4. Joe Greene of Dayton, Ohio, finished third at 27-4 1/2, giving the United States its second consecutive sweep of the long jump.

The U.S. track and field team could have had a fifth gold medal for the day if 100-meter champion Gail Devers of Van Nuys, another former Bruin, had not hit the final hurdle in the 100-meter hurdles and staggered across the finish line in fifth place. LaVonna Martin of Trotwood, Ohio, was second in that race.

Decathlete Dave Johnson of Pomona also staggered because of a stress fracture in his right foot. With Johnson far behind the leaders in ninth place after the first day of the 10-event competition, it appeared that Reebok might have nothing left from its marketing campaign except the ampersand. But Johnson persevered to earn the bronze medal.