OYSTER BAY, N.Y. (AP) _ John Eustice of Philadelphia, a three-time United States road race cycling champion, and Judy Caunter of Marblehead, Mass., head a field of approximately 500 cyclists in an international cycling race Sunday at the Oyster Festival.

The field in the 35-mile men's race includes Roberto Gaggioli of Italy, a member of Italian Olympic team who won the sprint championship at this summer's Coor's Classic, and Kim Eriksen of Denmark, who races in the 1984 Olympics and has won 112 races in international competition.

Caunter, who received the 1987 U.S. Olympic team sportsmanship award and won an individual gold medal and a team bronze at the Pan American Games, leads the field in the 20-mile women's race.

Davis Phinney of the 7-Eleven team, who won a stage at the Tour de France, and Debbie Stephan of the Peaugot team, are the defending champions.