Don King was flashing a confident smile and trying to show some muscle yesterday at Capital Center as he exulted over "a three-hour extravaganza" that will be telecast by ABC on Monday night, May 16.

The main attraction, of course, will be Muhammad Ali defending his heavy weight boxing championship against Alfredo Evangelista of Madrid.

Alfredo Escalera of Puerto Rico will defend his junior lightweight title against Carlos Becerill, a native of Mexico who fights out of Pomona, Calif., and lightweight champion Roberto Duran of Panama will box a 10-round nontitle bout against Javier Muniz of Los Angeles.

King, whose U.S. Boxing Championships tournament has been suspended by ABC pending its own investigation, made reference to that when he said, "We're having a resurgence in boxing.

"We're making the editorial page and the front page, as well as the sports page. I want to thank the press for making boxing as big as it is.

"The press has given us some black eyes, but that makes a fighter want to get and do better.

"We want Jimmy Carter and (Spanish King) Juan Carlos to come the bouts. We're going to do what politicians wish they could do."

He said he was referring to the fact that there would be four nations represented on the show - Spain, Mexico, Panama and, in addition to Puerto Rico - the United States and he nodded at the representative flags behind him two this country.

King took down a Pine Tree Flag, depicting a snake and including the warning, "Don't Tread on Me," likened the reptile's attitude toward his own, and said that it had been presented to him by Navy Adm. Jim Wilson when king's tournament bouts were conducted aboard the U.S.S. Lexington at Pensacola, Fla.

Again alluding to the controversies involving the tournament, King said, "We've just had some in-house problems in boxing."

At the speaker's table with King, were Centre owner Abe Pollin, matchmaker Eddie Hrica, Escalera, Becerill and his manager, Harry Kabakoff, and Chester O'Sullivan, chairman of the Maryland State Athletic Commission.

King was not reluctant to discuss the allegations of scandal involving his tournament. But he cautioned his interviewers to await the outcome of inquiries (being conducted by ABC, the Maryland commission and a federal grand jury in Baltimore).

He said the tournament was victimized by Ring magazine, which has been charged with publishing falsified record that enable some boxers to qualify for invitations to the tournament.

ABC wanted to be sure that Evangelista was ranked by international groups such as the World Boxing Association and/or the World Boxing Council before going ahead with a telecast of the challenger's bout with Ali. The network said yesterday it definitely will carry the bout.

Because Evangelista, a native of Uruguay who now fights out of Madrid is largely unknown, copies of his record as compiled by Ring were distributed at the news conference, along with a comparison of his physical dimensions with Ali's.

Ali drew 12,471 in his title defense against Jimmy Young at Capital Centre April 30, 1976. King said yesterday, "We want this to be a sellout crowd with Ali coming out of retirement (which he announced after winning disputed decision over Ken Norton)."

A press release issued by Don King Productions said that Evangelista is managed by Jose Luis Martin Berrocal, "one of Spain's leading businessman . . . the owner of seven farms breeding for the bullring. Berrocal is a resort and hotel developer and is a prominent antique collector."

Ali will recieve $2.7 million, Evangelista $85,000. The top ticket price will be $150 for "red carpet ringside." The lower prices will be announced today.