Floyd Favors, the amateur world champion bantamweight boxer from Capitol Heights, Md., won a split decision over Herb Bivalacqua of New Orleans tonight for the gold medal in the National Sports Festival.

Favors, who won the world championship earlier this year in Munich and is considered one of America's best hopes for a gold medal in the 1984 Olympics, drew boos from the crowd here when he spent most of the final round dancing away from his opponent.

"The crowd wanted a bam-bam fight. I came here to box," said Favors, 19, a graduate of Suitland High School. Bivalacqua thought he had outslugged Favors: "I thought I had it all the way. He didn't deserve the decision."

In the 106-pound class, another Washington-area fighter, 18-year-old Joe King, lost a unanimous decision to Bryan Jones of Philadelphia. King, who graduated from Archbishop Carroll High School this year, fought Jones evenly the first round. But in the second and third he began leaving himself wide open to devastating counterpunches by Jones.

The crowd here of 7,500 cheered loudest for a 125-pound bout between Bernard Gray of Florida and Chicago's Orlando Johnson. In April, Johnson beat Gray in a controversial decision at the U.S. Nationals, in Charlotte, N.C. But tonight there was no doubt as Gray stunned Johnson into two standing eight counts in the second round.

In other bouts, Jesse Benavides came back with long looping punches in the third round to upset Detroit's Steve McCrory in the 112-pound class. McCrory, the classier of the two fighters, seemed to have the match under control when Benavides began connecting with long-range left hooks and lunging rights.

In the 132-pound class, Pernell Whitaker of Norfolk decisioned a much taller but awkward Joey Belinc of Washington State.