ATLANTIC CITY, N.J. -- Hard-pressed though I was to tear myself away from the frenzied excitement of the Spinks-Cooney "War At The Shore" . . .

(Across the country dozens of people have shown an interest in this one; just the other day almost 40 closed-circuit seats were sold, leaving only slightly more than 36 million still available; promoter Butch Lewis, who has pioneered the classically formal yet deceptively casual tuxedo-sans-shirt look, says he is looking for a brisk, walk-up sale on fight night, but this thing is headed for red ink even if every man, woman and child in Europe starts walking.)

. . . nevertheless, I managed to take a break on Saturday night to see one of the truly spectacular entertainment packages of our time, a watershed in vocal stylings, and I'm speaking of course about what was introduced at the Sands as, "The world premiere of The Battle of the Singing Heavyweight Champs with Smokin' Joe Frazier and Larry Holmes, The Easton Assassin." And you wondered where the great new talent was coming from.

Smokin' Joe first started singing in 1971, after he'd beaten Muhammad Ali for the title. You'll no doubt remember his original backup band, The Knockouts. I'm glad to report that age hasn't withered nor custom staled his infinite variety. The line on Frazier's singing now is the same as it was then: "Okay, he's not great. But who's got the guts to tell him?"

Holmes, on the other hand, never had sung professionally before. And his debut startled a lot of curious ringsiders. Bobby Cassidy, once a highly ranked light heavyweight, said, "I never dreamed Larry could sing. I have trouble understanding his talking." But Holmes made his position clear as soon as he walked on the stage, saying, "If Joe Frazier can do this, why can't I?" (And again, who's got the guts to tell him?)

Frazier opened, wearing a white double-breasted suit, backed by three singers and a four-man band loud enough to drown out any false notes -- not to mention any nearby construction. He did a Stevie Wonder song, then "Stagger Lee," "Soul Man," "Bring It On Home" and a breathless, Barry White kind of version of "My Girl." Frazier was a classic straight-ahead fighter; lateral movement, unfortunately, was never his forte, and during some of his more exaggerated side-to-side choreography, he looked rather like a hippopotamus wearing a bedsheet.

After those recognizable songs, he took a drink of water (remembering he's no longer a boxer, he didn't spit the water into a pail), and said to the audience, "I know what you people are saying: When is Smoke gonna do an original tune?" Sure enough, he did three, ending with his apparent signature, "I'm Still Smokin' ". In all, Frazier did 30 not-at-all-unpleasant, hard-working minutes -- more time than Gerry Cooney's spent in the ring in the last five years -- and let me tell you, folks, this was not an easy act to follow.

Some of us wondered exactly what Holmes would do. Would he stand there and insult the audience, as he'd done to the fight press for so many years? Would he sing "Volare" and dedicate it to Rocky Marciano, whom he once bitterly said "couldn't carry my jock strap"? How many times would he do "My Way"?

Preceded by a seven-piece band and the obligatory three backup singers, Holmes strode on the stage resplendent in a black suit, tomato-red shirt and handkerchief, diamond necklace and five diamond rings. (Maybe Holmes went to the Sammy Davis Jr. Vocal Academy and they threw in a fashion seminar for free). His first number was an energetic rap song called "Boxing Politics," which asserted he was robbed in his bouts with Michael Spinks. Let's sing along with the Easton Assassin now: "I won that fight/They took it away/But that's okay . . . I trained real hard/To do the job/But I got robbed . . . Everybody knows I beat Spinks/Everybody knows boxing stinks." (I should mention there were numerous "Whoooooohs!" punctuating the lyric. Holmes gives good "Whooooooooh!")

I thought Holmes' band failed him by not playing louder in his next tune, an idiosyncratic version of "Under The Boardwalk." Then again, perhaps nothing, not even World War II, would have been loud enough. Let me put it this way: If you were stuck on a desert island with Holmes, and he started singing "Under The Boardwalk," you'd be swimming before he got to " . . . out of the sun." But to his credit Holmes cheerfully said, "Everybody knows I'm not a singer," and although he picked up a towel to dry off, he didn't throw that towel in. Displaying courage and versatility, he moved to the keyboards -- "I don't play this thing, but I'm gonna give it a shot" -- and accompanied himself on a jazzy production called "Make A New Move." (It was sort of like watching the regional quarterfinals on "Star Search." You kept wondering when Ed McMahon would come on stage with a fabulous sweepstakes magazine offer.) Holmes closed with a cathartic "Ain't Too Proud To Beg," and called Frazier back on stage to sing it with him.

As the curtain fell you could hear Holmes scream, "I don't want to stop." But the stage manager wisely ignored him. Frazier decidedly won the Battle of The Singing Heavyweight Champs, but Phil Collins and Billy Vera shouldn't lose sleep about the outcome. All in all, though, a worthwhile respite from the rigors of Spinks-Cooney.

And what a fight this one is shaping up to be. Did someone say The Snore At The Shore? Here's what people are asking: Which Spinks is fighting, Michael or Leon? And, will Cooney actually get in the ring, or will he find a way to postpone it? No wonder it isn't selling. Here's Spinks, a career light heavy who has three fights as a heavyweight -- two against an over-the-hill Holmes, and another against the alleged Steffan Tangstad. And here's the thunder-punching but reluctant Cooney, seven rounds in five years. Like the cicadas, Cooney doesn't come around often, but when he does, there's an awful lot of sound and fury, that, if he doesn't win here, signifies nothing.