Efrem Winters, a star basketball recruit at the University of Illinois, was kept eligible to play in high school and accept a college scholarship through altered grades, the Chicago Sun-Times reported yesterday. In the Midwest, Winters was as highly recruited and publicized as Billy Thompson, the Camden, N.J., center who decided to attend Louisville.

The newspaper said Winters' average changed from 1.2 on a 4.0 scale to 2.6 between the end of his junior year and the beginning of his senior year. He did not attend summer school. The university apparently had nothing to do with the changes, the newspaper said.

The Sun-Times said not only were Winters' grades changed but his entire course book, which records all his grades for four years, was replaced. Some of the signatures of teachers apparently were forged, the Sun-Times said.

A little-known Board of Education rule is interpreted to allow principals to change grades at their discretion and without giving justification. Teachers at King High School of Chicago said Principal Joseph Lee has done so many times in the past.

Lee, however, denied he changed Winters' grades.

"I have no knowledge of any grade-changing in Efrem's case," the Sun-Times quoted Lee as saying. "As far as I'm concerned, it isn't true. It is totally ridiculous. This is character assassination. This is dirt that people are trying to dig up. As far as I know, no grade-changing has taken place."

The newspaper quoted several teachers as saying it was clear the grades had been changed.

The Sun-Times said the NCAA will not have jurisdiction to investigate the case unless it can be shown the University of Illinois played a part in influencing the grade change, and that apparently was not the case, the story said . . .

In Atlanta, Perry Clark, 30, a former De Matha High School player and most recently assistant coach at Penn State, was named an assistant basketball coach at Georgia Tech.