The title flashed across the screen in red block letters: "PANCHO."

"We first met him, he seemed not interested in anything . . . ." The pediatrician's voice came soothingly across the film, narrating the changes that 5-year-old Pancho went through during his first year of Head Start, the federally funded pre-school program. Once listless, the voice said, the boy became healthy and active because of good medical care and the Head Start program.

The 1965 film ended, the changeliers went on again in the East Room of the White House, and Lady Bird Johnson introduced -- before the several hundred assembled -- Frank Pancho Mansera himself, now 20, sitting quietly in a three-piece suit in the front row.

Fifteen years ago, Mansera was among the first children to attend a Head Start Group and has become the program's most publicized success story. Yesterday was his second appearance at the White House, as a walking promotional monument to the success of Head Start and the administrators who brought him here to show him off.

The crowd of program directors, parents and teachers -- all involved in the first Head Start efforts, all devoted to the program, initiated by Lyndon Johnson as part of his Great Society -- gave Mansera a standing ovation. And there was more: HEW Secretary Patricia Harris was standing on the podium next to Lady Bird Johnson, and President Carter minutes later swept into the East Room to give a 20-minute emotional endorsement of Head Start.

"Oh, wow, I didn't know what to say," said Mansera afterwards. "My hands started sweating."

But he gathered his composure, and even had to fight to keep from dozing off a little. "During President Carter's speech," he said grinning. "The lights, they were getting to my eyes. A couple of times I thoough I would fall asleep."

"We were so worried about how he'd react to the movie," said one person traveling with Mansera. "But he said it would be no problem."

"At times it felt good," Mansera said soberly about watching his transformation on film 15 years later. "At times it felt sad."

He grew up in the southern part of San Luis Obispo County, Calif., and still lives there -- in the small town of Nipomo, a valley of orchards and migrant working families.

"It's in the middle of poor and modest," he said, smiling. "Sometimes it's good times and sometimes it's bad."

Mansera graduated from high school in 1978, and now has a full-time job in a nursery, tending plants. He plans to go to Allan Hancock Colege in Santa Maria, Calif. "I decided I needed to know more about plants," he said. "I want to do that and study a little carpentry. I like to have more than one thing."

He is not aiming for a degree. "I don't think so," he said, shaking his head matter-of-factly. "Maybe, I'll just go to the point where I know enough. Right now, at most about three years. I'll think about a degree later. Maybe I'll apply for a grant."

He traveled here from California with an entourtage including California Head Start administrators, his former Head Start administrators, his his former Head Start teacher Henry Grenan (who wore his Minolta camera around his neck), and the pediatrician in the film. Dr. William Tibbs had diagnosed Pancho Mansera's thyroid problem at age 5 under Head Start's policy of providing children with medical exams -- and helped him on the road to physical recovery and a normal life.

In Washington, it was Mansera's day as much as it was the program's. He was patted on the back and shoulders by his friends in Head Start, and by the HEW official escorting him around. People pulled him aside to whisper funny stories in his ear. He laughed, smiled -- all sincerely -- with the purveyors of all this attention, who seemed clearly delighted with him.

Mansera's first invitation to the White House came at the age of 6 -- on another promotional tour for Head Start Yesterday, that moment was captured for memory in a large black and white photograph of him peeking mischievously to his side as he stood in line with President and Mrs. Johnson.

"The devil," Mansera said of his expression in the photograph. "I never felt I'd [come to the White House] again. I just felt the last time would be it. Then they called me up last week and asked me if I wanted to do this . . ."

Other services he provides for Heat Start include handing out diplomas to children on "graduation night."

"Maybe I'd like to get into the Head Start program," he said reflectively, "work with little kids."

Unlike his friends, Mansera never worked in the fields picking strawberries and lettuce (although for three months he picked avocadoes -- somewhat easier work). "I've never done it," he said, crinkling up his nose. "I didn't feel right going down there -- like I wouldn't have accomplished what I was supposed to do."

He grew up with six brothers and sisters, all younger than he. His mexican-born mother is a housewife, and his father is on leave from his construction job due to disability.

"If there ever was a program that had invested in the future it was Head Start," President Carter said in his remarks yesterday, noting that children received a "head start in nutrition, education, health, self-confidence, esteem . . ."

Carter was involved in a Head Start program in Georgia during its early years. Sometimes, he said, he would go and watch the children:

"Many of then had never seen a book, never held a pencil . . . some didn't know their last names. I was a tough, young, conservative Georgia farmer," he said. And the program, he said, touched his life.

Pancho Mansera, summing up his own life, paused when trying to evaluate what Head Start had done for him. "It hasn't changed my life," he said, "I'm still me."