Joe Mullenax of Cumberland, Md., who led by 182 pins before yesterday's finals, won his first three head-to-head games and breezed to a 209-pin victory in the boys handicap division of the All-America Youth Bowling Championships at Shirley Bowl America in Alexandria.

Jeff Rampart (boys open), Joleen Kirvin (girls open) and Lenore Wong (girls handicap) were the other winners of $1,000 college scholarships.

Mullenax bowled his best two games to begin yesterday's round and erased any thoughts his opponents might have had of catching him.

"I felt that if I won two games today I'd have no problems," Mullenax said. "Also I pefer playing head-to-head competition. I always seem to bowl better against someone as opposed to just score."

Mullenax finished the tournament -- 32 games -- with 4,823 pins. Michael Finnegan of Bloomfield, N. J. was second with 4,614.

Rampart of Kenosha, Wis., began the day in fourth place, 94 pins behind division leader Bob Davidson of Seattle, but Rampart bowled a 935 series (a 233.7 average) and defeated Davidson in the final two head-to-head games to win the division.

"Today I wasn't worried about anyone jumping over me when I moved up," said Rampart, 15. "I just concentrated on my shots instead of on the other players. "I thought if I averaged 220 I could win," he added. "But if I didn't open the first game with six strikes I might not have won. Those strikes made me feel that I had a real shot."

Rampart's six strikes helped him to a 244 -- his best game of the day -- and while Davidson rolled an opening 242 he couldn't sustain that average. His final three games were 185, 204 and 179. Davidson's downfall in the final game was two key open frames, both splits, in the first and seventh frames. Kirvin, of Pembroke Pines, Fla., overcame an opening 145 to beat Vicki Parker of Nashua, N. H., 4,432 to 4,321.

Wong, 15, from Monterey Park, Calif., was in first place all four days and finished with a comfortable 4461-to-4,295 win over Teri Webster of Scottsdale, Ariz.