Gary Williams, assistant coach at Boston College and captain of the University of Maryland's 1966-67 squad, is American University's new basketball coach, Washington Post learned last night.

AU has called a 2 p.m. press conference for today to unveil Jim Lynam's successor. Lynam resigned last month to become head coach at St. Joseph's, his alma mater and AU's rival in the East Coast Conference.

It was learned that Williams, 32, was the unanimous choice of a five-person advisory panel to AU Athletic Director Bob Frailey. Only four candidates had been formerly interviewed - Williams; Wil Jones Maryland assistant and former AU All-America; Joe Boylan, former AU assistant who is currently an assistant at Rutgers, and Alan Srebnick, Lynam's top assistant at AU.

Williams could not be reached for comment, but Tom Davis, another former AU assistant under whom Williams served a total of seven years at Lafayette and at Boston College, said:

"He will be an outstanding head coach. He knows the competition, AU's basketball history, what it takes to win in the ECC. He knows AU's recruiting territory, has strong contacts in Pennsylvania, New Jersey and New York. He won't have any trouble becoming familiar with the program.'

In Maryland's 1966-67 basketball brochure, Williams, a 6-foot playmaking guard and teammate of Jay McMillen and Joe Harrington, was described as "a fierce competitor with a heart as big as his chest."

It was Bud Millikan's final season at College Park. The next year, Williams became a graduate assistant at Maryland under Frank Fellows. The full-time assistants were Tom Young and Davis. Two years later, they moved together to AU.

Williams, a New Jersey native, then spent three years at Wilson High School in Camden, the final two as head coach. In the first year of his first head-coaching job, his team was the unbeaten state champion in New Jersey's highest classification.

After Williams' third year there, Davis progressed from his AU assistant's job to the head-coaching position at Lafayette, and hired Williams as his chief aide.

"He was totally gung-ho and impressive the year he was a graduate assistant," said Davis, explaining what prompted him to hire Williams. "He was totally dedicated to basketball."

When Davis left Lafayette after the 1976-77 season, Williams was asked to succeed him, but he turned Lafayette down and accompanied his boss to Boston College.

At AU, he will inherit a 16-12 team that lost only two seniors and will have three transfer students available by the second semester.

Williams will have two full-time assistants, the same as Lynam. The top possibilities include current assistants Srebnick and Wilbur Thomas, a former AU star player, and two former Lafayette players - Tracy Tripucka interim coach at Fordham last season, after serving assistantships there and at Navy, and Jay Mottola, assistant at Muhlenberg.