George Foreman is old, but it's a shame he isn't old enough for P.T. Barnum to have seen his act.

Boxing's funny man led sports' most bizarre -- believe it -- cross-country roadshow to its last stop in Washington yesterday. By now, every George-is-old, George-is-fat and George-is-slow joke has been honed, the whole show pared to a fast-moving 60 minutes so that actually it would make a hilarious TV comedy hour, kind of modern-day Milton Berle slapstick.

In one of the few moments when the laughter dies, however, heavyweight champion Evander Holyfield suggests with a foreboding look and tone that Foreman may learn that "over 40" indeed could be a "death sentence" when they fight in April. But there's little seriousness involved in the great hype of "The Battle of the Ages!" Pointing up that the "battle" is being sold on the thin theory that an old man could beat a prime-of-life physical specimen with a one-punch knockout, Holyfield's corner man, plump Lou Duva, drew a roar of laughter with a timely pronouncement. "Boxing," he said, "can be summed up in one word: You never know."

Really, the only question is where the final act will be played out. This week, Donald Trump demonstrated again that he's suffering financial shorts, declaring that he wants to renegotiate his promised $11 million Atlantic City site fee and the due date for a $2.5 million payment on the scheduled April 19 bout. Trump and Dan Duva of Main Event, which promotes Holyfield's fights, will meet today in Atlantic City. Both Duva and Bob Arum of Top Rank Inc., which promotes Foreman's fights, said here yesterday that they'll take the fight to Caesars Palace in Las Vegas and hold it there April 26 if Trump reneges.

There's a so-called "act-of-God" clause in Trump's deal with Duva and Arum, as well as a "war clause." But Duva called Trump's hint that he may back out "an act of Trump."

Arum, red in the face, called it "diabolical" and "unethical" and that he knows every Trump trick in the book because "I've read his book."

Never was it more apparent that Trump is facing hard times, because he could possibly miss out on one of the craziest times ever in boxing. "Big" and "biggest" were the most often used words yesterday. Foreman, who is 42 or 43, is so big that Lou Duva said he has a birth certificate showing that Big George was born on "Jan. 22, Jan. 23 and part of the 24th."

Much was made of Foreman's eating habits -- the champion of fast food, he has been known to order whole menus. The Ramada Renaissance Hotel people gave him not the key to the city -- the key to the kitchen. "That's what I've always wanted," said Foreman, holding up the big key.

But Lou Duva professed: "He's a light eater." (Pause for effect -- he's got this down because the tour began 8 or 9 or 10 cities ago). "As soon as it's light, he eats."

Foreman was dressed in folksy attire -- a red lumberjack shirt, black leather vest, dark tie. His bald head looked like the dark side of the moon.

He looked like your grandfather. In fact, it was Jan. 22, 1973, when he knocked out Joe Frazier to win the heavyweight championship. How improbable that, at this late date, he has another chance to win the title, based on 24 straight victories against suspect opposition since returning to the ring in 1987 after a decade's layoff. "I think there should be a retirement age for boxers," Foreman said. "Sixty-five."

A tape was shown of Foreman beating Frazier. That was followed by Foreman beating Gerry Cooney on Jan. 15, 1990. Laughter rippled through the audience. Foreman, big and bald, simply was unrecognizable as himself.

A fighter that old has to have an old trainer, and who more fitting than Archie Moore? "The Old Mongoose," wearing his purple beret, is about 78. He first fought Piano Man Jones in Arkansas in 1935, and was about 48 when he was knocked out by Muhammad Ali in 1962. Moore is the best light heavyweight there ever was.

But he's a comic too. "I don't want to tell you about the fight," he said, putting up his dukes and bobbing a little bit. But . . . he did. "The bell rings. They come out. They meet. Bing, bing, bing, bing, bing. Evander goes back to his corner. Lou Duva wipes his blood, sends Holyfield out again. Holyfield throws a lot of punches. George has a cut on his eye. He comes back to the corner. I send him back out again. {With a rising voice} They slug it out in the middle of the ring and they have the crowd standing up, screaming. . . . Well, next chapter next week."

Holyfield -- black turtleneck, dark doublebreasted jacket -- said he thought Big George -- the father of five Georges -- has to be "off his rocker" to get into the ring with him. "What rocker?" Foreman asked.

Foreman still fighting, Dan Duva said, is "akin to Sonny Jurgensen coming out of retirement next season and leading the Redskins to the Super Bowl."

Holyfield may be in spectacular condition, Arum conceded, but nobody works harder than Foreman. Arum said that Foreman not only isn't always eating but that he spars in the gym twice a day "except for Sundays, which he {being a minister in Houston} devotes to his congregation."

Foreman stretched his arms up to the heavens and said: "People say, 'George, you're kind of a role model for senior citizen types.' I stopped smoking when I was a teenager, a little kid. I saw my friends running around. I said, I'm not going smoke and drink, I'm going to be productive when I get to be about 60 or 70.

"Evander Holyfield, they say he's strong and he's tough. But I need him to be strong and tough. David needed Goliath to be strong and tough, so that he could go down in history. I don't want a wimp.

"I need a guy with muscles. I want him to get in the ring and people say, 'What has he been lifting?' And then when I get in the ring they'll say, 'What has he been lifting, hamburgers?'

"I want it like that. I like being my age. People are going to begin to use the word 'potential' and 'possibly' and 'the next' and 'the future' along with 40 and 45. I'm going to be the next heavyweight champion of the world. This is my destiny."