At 10:46 Sunday morning, a single bugle will play the heartache of "Taps."

Thirty-three men sitting between fuel cells carrying 35 gallons of explosive methanol will have heard, the minute before, words of memorial for this nation's soliders -- and racers -- who have been killed. It is sport's most chilling moment. At 11 o'clock, the bugle silent now, the 33 cars will go 200 mph in the 65th runing of the Indianapolis 500 (WMAL-TV-7) will show the race on tape at 9 p.m.).

Some facts: two-time winner Bobby Unser, 47, will start from the pole position, thanks to his qualifying run of 200.546 mph. With him in the front row will be journeyman Mike Mosley, 34, and A.J. Foyt, 46, the only four-time winner.

More facts: last year's winner, Johnny Rutherford, starts from the middle the second row. Four other former winners are in the field: Gordon Johncock, Al Unser, Rick Mears and Mario Andretti. There will be 10 drivers making their first 500 start, including Josele Garza, 22, a Mexican who astounded the racing fraternity by qualifying sixth-fastest at more than 195 mph.

The last bunch of facts: where the 1980 race was all but conceded in advance to Rutherford and the sophisticated Jim Hall "ground-effects" car, Sunday's 500 will be more competitive. "Everyone has caught up with Rutherford," said Tom Sneva, who finished second last year. "There are maybe 10 to 12 teams that can win now." Sneva's qualifying speed was the fatest ever (200.691), but he will start 20th because he missed the first day of trials.

Now, a question: why doew anyone dare to do this dance of death?

The answer is simple, complete and beautiful. these 33 men come to the dance because to stay away is to be less than they are.

Sing me no song of magnetos and flywheels, tell me no tales of chassis and turbochargers. Leave the mechanics to others such as the Indianapolis newspaperman, George Moore, who, bless him, wrote this sentence today in praise of the dominant Cosworth engine: "This basis is double-overhead cams and four valves per cylinder, an arrangement in which it is possible to achieve maximum valve area per given amount of displacement."

Tell me about the men who, in the test pilot jargon, "push the envelop." They take themselves to the edge, pushing against the invisible sides of the envelope that wraps our everyday lives. Tell me about A.J. Foyt, a millionaire who yet races for relative pennies. "I'll drive as long as I want to win, and I still want to win real bad," said the pugnacious Texan who, two weeks ago, jerked a reporter around by the hair for suggesting he cheated. This week, Foyt filed a $3 million libel suit against the reporter's newspaper.

Tell me about Mario Andretti, who said at a press conference he loves racing for its risks. He does no such thing. Only dummies race for the risks. The good ones like Andretti love the art of racing, love the precision of a turn, that intricate inch-off-the-throttle, tap-the-brake, watch-the-wall balancing act at the edge of control.

They love the risk only because it is a pretty frame for the masterpiece they are painting at 200 mph.

Tell me about Tom Sneva, once a schoolteacher but a racer forever.

Ed Sneva was a great racer in the Northwest in the '40s. His three sons wanted to be like their dad. At 32, Tom has finished second here three times in the last four years. At 31, Jerry is making his fifth start here. The oldest brother, Ed Sneva Jr., was killed racing in Canada in '72 three years before Tom got upside down and could have died at Indianapolis.

"I've seen the film of that wreck," said Sneva, who missed only a week's racing after his car became a flaming pinwheel bouncing through Turn Two. "I've seen it more than I want to see it."

Why dance again?

"This is," Sneva said, tilting his head toward his race car, "me."

For every lap Sneva runs on this Sunday before Memorial Day, the American Legion has pledged to donate $5,000 to the building fund for the Vietnam Veterans Memorial to be built in Washington. That could amount to a pledge of $1 million toward the estimated $7 million the memorial will cost. Through the Legion, Sneva is soliciting pledges from other Americans, "anything from a penny up."

Yet if you ask Sneva why he is doing this Vietnam memorial thing, he doesn't really know.

He went to college, not to Vietnam. He became a teacher, not a soldier. He took up a middle, safe ground during the late '60s when Vietnam tore at the conscience of this counrty. He wasn't sure we ought to be there, he said, but since somebody made the decision to go, he supported it. In 1969, when a president had quit because of Vietnam and a new one would make up an enemies list of prominent Americans, Tom Sneva drove a stock car the first time, not a tank.

"Out here," he said, meaning in racing, "maybe you don't take time to stop and think about what was happening in Vietnam. I guess it wasn't until the hostage thing blew up that I really thought about how much we had ignored the Vietnam veterans. I wanted to do something for them."

Racing left no time for Vietnam; racing owned Sneva.

There is the beauty of it.

When racing, these men are alive. Hifetz with his violin made no greater art than Jackie Stewart moving a Lotus through a turn in traffic. At Indianapolis, with it four seemingly identical but astonishingly distinctive turns, the winner is never a charger with his brains in his right foot; the winner here has done delicate, precise, brave work that only a few seek out and even fewer can do.

You count on one hand the number of race drivers who earn as much in a year as some utility infielders. Yet they make a commitment that, to a lot of us safe in our envelopes, is incomprehensible. They don't race for the money, or the risks, or to help build a memorial to men who died in a war they missed.

They race because they can't not race, and by pushing the envelope they show us all what it means to be gloriously alive.