Hugh Weisman organized the first Chilmark Road Race in 1978 as a fun run for the kids at the Chilmark Community Center. He never imagined that tomorrow, he'd be presiding over the 25th annual event, nor that the road race would grow to landmark stature on the calendar of the Island summer.

"It's been very gratifying," said Mr. Weisman, who now gives up a week of vacation every year to run the race. "I ran into somebody in New York this winter who says he lives for the road race - he's flying up for it.

"That kind of thing makes it worthwhile," he said. "It's fun to see the same faces year after year."

The race, which had about 180 runners in its first year, grew quickly until the town persuaded Mr. Weisman to cap the event at 1,500 runners in 1992. The race, beginning 10 a.m. Saturday, follows Middle Road, starting near Tea Lane and ending at Beetlebung Corner. The Chilmark Community Church Flea Market takes a Saturday off each year on the day of the race.

Mr. Weisman says one of the trickier aspects of managing the Chilmark Road Race is getting the registrations to work out right. He'll actually be accepting a few late entrants tonight at the community center, starting at 5 p.m., to complete the field.

There's a great deal of tradition to the race, including the first prize of a fresh lobster. But this year there's also a new twist - the road race is going high-tech, with a computerized system for tabulating every runner's time.

"This year we're using electronic chip timing," Mr. Weisman said. "Runners will be issued an electronic chip with a velcro strap for their ankle - their numbers and times are recorded as they cross the finish line. The end result is that we can get results out almost instantly, and they're very accurate."

Said Mr. Weisman, who knows a lot about both the good and bad of computers from his work in New York, "This is going to be very slick. And if it doesn't work, it's going to be a fiasco."

Folks already registered for the race need to check in at the community center to receive their ankle chips and T-shirts either tonight from 5 to 7 p.m. or Saturday beginning at 8 a.m. Shuttles carrying runners to the starting line begin service at about 9 a.m. tomorrow.

Mr. Weisman expressed his appreciation to the corporate sponsors, who are providing Naya Water and Clif Energy Bars at the finish line. He said the road race has consistently raised about $5,000 a year for the community center, "so it's probably come to about $100,000 over the years," he said. "Painless money, except for me."

On a final history note, Mr. Weisman said, "We've had two runners, Morgan Shipway and Priscilla Karnovsky, who've run in every race. I don't see either of them giving up, so I suspect that when we have the 50th anniversary road race, they'll still be plugging away."