The Prince William County School Board has ended a four month nationwide search for a new school superintendent by deciding to promote Richard W. Johnson, an assistant superintendent, to the job.

Johnson, 40, has overseen school construction for the rapidly growing school system, fourth largest in Virginia.

Starting May 5, he will serve out the 13 months remaining in the four-year contract of William L. Helton, who left the superintendency in January for a staff position with the State Department of Education.

According to Phyllis O'Toole, chairman of the school board, two consulting firms were used in the search for a new superintendent and 80 applicants were screened.

During the last month the board interviewed seven candidates for the job and decided by a 4-to-3 margin Thursday night to select Johnson.

O'Toole said the most difficult task $99(TEXT OMITTED)$99 the majority because she preferred another candidate, but she said yesterday Johnson will "enjoy the full support of the board."

O'Toole characterized the new superintendent as "very popular and well-liked."

"O'Toole said the most difficult task facing Johnson will be persuading the Prince William County Board of Supervisors to approve the school system's proposed $90 million budget.