It could be the last dance - the last hurrah for Muhammad Ali tonight, but his fans don't want the cheering to stop.

He is more than a heavyweight boxer, of course, an international symbol of the generation of the black revolution in America and an encouragement to a Third World reaching for self-determination.

Ali, originally named Cassuius Marcellus Clay after an abolitionist, is talking grandly about a larger mission to the world after his attempt to win back his championship from Leon Spinks, but he probably will discover that his power base will shrink like an apple in the attic once he takes off the gloves.

Where else but in edifice called the Superdome would it be proper to say thanks for the memories to the 36-year-old warrior? And on home television, beginning at 8 p.m. on WJLA-TV-7, with the main bout between 10 and 10:15.

The memory of the brash Louisville Lip, a laughable underdog, confusing fearsome Sonny Liston, first by pretending he was frantic with cowardice at their physical examinations and throwing tantrums, then taunting him in the right before the old gaffer quit cold.

The recollection of a high school nonachiever sensing, before our professional statemen, that Vietnam was wrong, braving criticism in refusing induction into the armed forces, and being stripped of his title for 31/2 years.

The memory of Ali stunning the establishment by disclosing that he had discarded the Baptist faith of his parents joined the Black Muslims and had changed his name. . . the three classic bouts with Joe Frazier . . . the gamble he took when he dared to let George Foreman punch himself out on his anatomy before knocking him out . . . and then the struggles against the lesser talents - and the erosion of his reflexes by the aging process.

Yet, he has rallied form the defeat by Spinks, a veteran of only seven professional bouts before that night seven months ago in Las Vegas, and from dreary workouts here, to be an 11-to-5 favorite in the rematch against the 25-year-old former marine.

Elvis Presley's rock and roll was "in" when Ali began his rise to be the best-known man on the globe. Now the question is whether, despite the odds. Spinks will make Ali dance attendance to his disco beat, as he did in winning a split decision the last time.

Spinks weighed in at 201 pounds yesterday, 3 1/4 more than he did in Las Vegas. The wise guys were trying to read into that slight gain whether the champion has been carousing occasionally or merely maturing.

Ali came in at 221, or 3/4 pounds less than he did last time. It's harder to lose pounds at age 36, but it was four more than he was projecting.

The former champion has had 50 more professional bouts than Spinks.

He has won 55 fights, 37 by knockout, and lost three - to Joe Frazier in their first encounter, to Ken Norton in their first of three bouts, and to Spinks-all by decision.

Spinks is unbeaten in eight fights, but figured in a draw with Scott Ledoux and was unimpressive in decisioning Alfio Righetti, a prudent boxer, in 10 rounds. Spinks scored knockouts in his first five bouts, three in the first round, but is not regarded as a one-punch finisher.

Ali has indicated that he will go quietly from the boxing scene, rather than taunting and screaming. He disdained the usual fuss at the weighing-in ceremony and there was no confrontation because the fighters made the trip to the scales separately.

Rival promoter Don King was present with his principal attraction. Larry Holmes, who was acclaimed as the World Boxing Council champion after he defeated Norton, but there was no exchange or remarks.

Technically, Spinks is defending only the World Boxing Association title, because the WBC withdrew its recognition after Spinks declined to fight Norton before giving Ali a return shot. But the fans mostly recognize Spinks as champion of everything because a decisioned the man they regarded as the true world champion, Ali.

It is speculated that the bout to night will probably go the scheduled 15 rounds, because neither boxer has a tin chin.

In fact, Spinks has not been on the floor as a professional and only once in 185 bouts as an amateur.

Ali has been boxing professionally for 18 years, since Oct. 29, 1960, and has been put down, but not out, four times-by Sonny Banks, Henry Cooper, Joe Frazier and Chuck Wepner (disputed knockdown). Former light heavyweight champion Bob Foster once put Ali down as an amateur.

Ali has shown a punch in the past, when he was able to combine his strength with hand speed to produce power. He knocked out Liston in their second bout with a punch of disputed force and showed impressive power in knocking out Foreman.

Yet he has had to go to decisions in five of his last six bouts, outpointing Jimmy Young, Ken Norton, Alfredo Evangelista, Earnie Shavers, and losing to Spinks.

Ali attempted in his first bout with Spinks the strategy of trying to get Spinks to punch himself out in Spinks' first fight scheduled beyond 10 rounds.

Ali gave away the first five or six rounds, turned on some pressure in the 10th, when he appeared to have Spinks ready to go but couldn't deliver, then began fading in the last five, although making the 15th lively for a while.

Ali says that if he could go 15 the last time, the last five rounds on pride, he can do better this time with harder training. Yet, it is expected that he will try hard this time to end it quickly against the dourable champion.