Muhammad Ali relaxed at a postfight press conference yesterday and dodged questions about his future as easily as he had slipped the punches of Leon Spinks Friday night in winning the world heavyweight title an unprecedented third time.

At times, the champ hinted that he might have a future in the ring, but he also suggested that other endeavors might be more appealing to a man of 36.

The picture was complicated a bit by Bob Arum, head of the Top Rank Inc. promotional firm, who said he has an option on Ali's next three fights. And there was an unconfirmed report that Ali's manager, Herbert Muhammad, already has contracted for two more bouts, a claim Arum contradicted.

But Ali would not speak of contracts or firm agreements.

"If they give me $10 million after taxes," said Ali, "I'll fight. Holmes is 28. If they'd make him 36 like me, I'd sign tomorrow. Or let me be 28.

'I'm going to keep the title six to eight months and then make a decision. If I said I retired last night, they'd take the title away. I'm going into business as a champion (to exploit his identity as such) with 'Champ Export Ltd.,' dealing primarily in Third World countries.

"I might fight again and I may not. You'll have to wait and see."

The new champion said President Carter called him after the bout, congratulated him and told him that Menachem Begin, prime minister of Israel, and Anwar Sadat, president of Egypt, also watched the telecast of the fight at Camp David in Thurmont, Md.

At one point in the wide-ranging interview Ali said, "I'm getting out of boxing. Boxing was the dressing room, a preliminary to the big fight - for humanity, racial justice, freedom and human rights . . .

Might he be Ali's next opponent?

"If he doesn't lose, like Ken Norton did after he lost to me."

Could Spinks beat Holmes?

"Oh, man," Ali said as if surprised by the naivete of the questioner.

"Spinks has faster hands. Holmes is just jab, jab, jab, jab.

"Did you see that crowd paying that money - 70,000 paying $6 million? That was a hell of a way to go out."

Ali reminded his occasional critics: "Joe Frazier got me (won by decision in the first of their three fights) and they thougt I was through; Ken Norton broke my jaw (in the first of their three bouts) and they thought the same; then Spinks did.

"I always find a way when the money is on the table, when the people are in the arena, when the headguards (used in training) are off, when the pressure is on."

What was Ali's plan to beat Spinks?

"By moving. Did I look old with that 25-year-old Spinks? Who looked older?"

Ali was asked what he and Spinks talked about during the fight. "We were just trying to psych each other," he replied, "I won't tell you what we said."

Arum said: "You saw last night a great tragedy for boxing, and for a human being. Maybe I was at fault for putting Leon in a championship fight (the first time) when he wasn't mentally ready, when he wasn't ready to accept the responsibility of being champion.

"We knew he had tremendous raw talent and might take the title because Ali might take him lightly. I don't want to take anything from Ali but he was fighting a fighter who had retrogressed since February. His training camp was in total chaos. There were people trying to get their hooks into him.

"I suggest that he listen to George Benton, whom I regard as the best teacher and trainer around.

"You saw the spectable in training of a champion being educated in fundamentals the week before the fight. Leon wanted to listen only to Benton . . . He didn't have the guts to tell the other people around him to leave him alone.

"There were dozens of sharks picking at the bones of a young fighter."

Arum reportedly had Spinks lined up for a bout with Kallie Knoetze of South Africa for $1.35 million and a bout with Norton for $3 million.

But yesterday, Arum said that Spinks might never fight again.

"Leon has got enough money so that he doesn't have to," he said. "He doesn't like to train, and he won't until he runs out of money. He doesn't spend in the style that Ali does, and Leon's money should last a long time."