THE PRESIDENCY : Truman Library Seeking Bigger Volume of Youths : $10-million renovation would modernize exhibits to appeal to younger visitors who are unfamiliar with F.D.R.’s successor.

The front steps of the Harry S. Truman Library were overrun with elementary school students the day the institution marked the solemn moment that Franklin D. Roosevelt died and Truman stepped in as the nation’s 33rd President.

Shivering under a stiff April wind, the schoolchildren stood for the Pledge of Allegiance, whispered and giggled to each other as a succession of speakers praised Truman and gaped as a squad of soldiers fired off a 21-gun salute.

It was a fitting presentation: This year marks the 50th anniversary of Truman’s ascension to office. He built the library as a “place where young people can come and learn what the office of the presidency is . . . no matter who happens to be in it at the time.”

But even as it celebrates its namesake’s accomplishments, the Truman library is in the midst of an ambitious effort to raise millions of dollars and modernize its exhibits to attract new generations of young Americans who barely recognize his name. Still in its early stages, the renovation project faces fund-raising complications and delicate internal questions over how far the museum should stray from Truman’s original intentions.

Inside the museum, a 100,000-square-foot structure with the homespun air of a rural stopover, officials insist they can boost attendance and teach new generations about Truman and the American presidency through a planned $10-million renovation.

Their changes would include redesigning much of the museum’s interior and replicating the West Wing of the White House. But the most drastic addition would be the installation of video screens, interactive computers and electronic displays, the sort of wizardry standardized in the openings of the Ronald Reagan and Richard Nixon presidential libraries.

“The feeling is that the museum has been satisfactory for older people, but isn’t fitting the need for youngsters who would come in and couldn’t identify with exhibits that simply laid it out in a few black and white pictures and displays,” said museum director George Curtis.

Despite Truman’s continuing good standing in recent polls and the best-seller success of historian David McCullough’s Pulitzer-Prize winning biography “Truman,” many students visiting the museum show only a vague understanding of his life and role in American history--even those who are growing up in his hometown.

“Let’s see,” said Gabe Brown, 11, a fifth-grader from the neighboring Bryant School who has visited the museum twice and best likes an exhibit of 1940s-era cars. “He was President for a little bit after Roosevelt died. He always took a walk at his house.”

Museum officials point to statements like this as evidence that they need to make Truman’s life more vivid to visitors. Yet Curtis acknowledges that there is an internal debate going on over how much should be changed.

“We have to be careful,” he said. “Over 80% of our visitors are seniors. These visitors don’t really . . . dig . . . the gadgetry and wouldn’t be comfortable sitting down and working with computers.” Instead, Curtis said, short video presentations and precisely aimed interactive exhibits might fit in best with the older exhibits.

The library that visitors roam through these days is hardly state-of-the-art. Its galleries are dimly lit and often haphazardly arrayed.

One display case houses a trove of gifts sent to Truman by well-wishers: A doll of his wife, Margaret; the “Puttnik,” a model of the Sputnik fashioned from a golf ball and tees; a giant Shriner’s fez and a coffee mug with Truman’s face. Down the hall is a six-foot-long model of the battleship Missouri. “We’ve tried to put it in storage,” a museum aide said, “but every time we do, the kids go nuts.”

The museum’s simplicity, however, has made it a lure to some visitors. “I think it’s an outstanding museum,” said Walter Dale, 69, visiting with a group from the Liberty Methodist Church. “They don’t hurry you through and there’s no gizmos and blinking lights.”

Historians like Robert Ferrell, an Indiana University scholar who is one of the most well-respected authorities on Truman’s life, offers a similar appreciation. Having spent almost three years poring over the museum’s research collection--14 million pages of manuscript, 90,000 photographs, 400 films and 40,000 books--Ferrell has a keen awareness of the museum’s need to modernize, but finds its low-key displays “endearing.”

Ferrell, who recently published his own highly regarded Truman biography, said the proposed redesign “goes beyond Truman’s rather modest idea of what the museum should be.”

Ultimately, the museum hopes to have $10 million to pay for the expansion and another $25 million to defray operating costs that will arise if the federal government withdraws from paying operating costs, said Phil Fleming, the library’s director of development. Officials worry that their funding--$2 million last year--will be slashed by a Congress eager to balance the federal budget.

For the moment, visitors drift through the library as they always have, children crowding around the old battleship, older visitors pointing out the politicians and celebrities that only they can remember.

Ferrell hopes they all come away with “a celebration not of the man, but of the job. If they leave with a little better feeling for what it takes to be a President, then the place is still working.”