Viloria, 15, won three bouts en route to reaching the finals.
Marc Manuel, also of Waipahu, lost his championship bout to earn a silver medal.
Admission to the SPORT exhibit and all activities will be free for local residents with identification.
The day begins with a breakfast of champions from 9 to 11 a.m. with Hawaii's Olympic champions.
In addition, it will be the kickoff of Woody's Hot Dogs Keiki Hawaiian Games, a competition for youngsters ages 5 to 12 in four traditional Hawaiian games from noon to 3 p.m.
The Keiki Hawaiians Games also will be held on July 14 and 21 at Bishop Museum.
For further information, telephone 847-3511.
The 182-pound main event will feature Navy man Jim Sullivan, a Chicago native, against Puerto Rican native Aldemir Lugo of Kailua.
There also will be a women's bout pitting Sharol Deocares against Noel Domen.
Admission is free.
The state meet is scheduled for July 13, beginning at 7:30 a.m., at Cooke Field on the University of Hawaii campus. The event winners may qualify for the Pacific Southwest Regional team that will compete in the national meet Aug. 10 in Hershey, Pa.
Registration is free, with forms available at all city and county playgrounds, track clubs and military recreation facilities. For information, contact chairman Dennis Arakaki at 586-6050.
He will play in an intersectional competition at Shreveport, La., starting Saturday; in the National Clay Court Championships at Nashville, Tenn., July 13-20, and in the National Hard Court Championships at Kalamazoo, Mich., July 29-Aug. 11.