The eligibility subcommittee of the NCAA Council today upheld a ruling that 7-foot-1 center Tito Horford, last year's prize high school basketball recruit, is ineligible to play for the University of Houston.

In another development on the eve of the 80th annual NCAA convention, leaders of the predominantly black schools in Division I have decided against walking out Monday if they lose votes on two proposals to remove test scores as a standard for determining the eligibility of freshmen.

Meanwhile, a source close to the NCAA investigation of Horford's controversial recruitment said there was a 50-50 chance that the athlete would enroll at UCLA this week.

Horford, reached by telephone in Houston, declined comment, and Pat Ellis, his attorney, said Horford "will make up his mind in the next couple of days what he's going to do."

Ellis declined to rule out the possibility that Horford might sue the NCAA or forgo college basketball. Houston's chancellor, Richard Van Horn, said previously that his school would abide by the NCAA's decision.

"Right now Tito's extremely upset with the NCAA," Ellis said. "He felt he was very cooperative with the NCAA investigation (at Louisiana State and his overall recruitment). He feels he's been hurt. He can't play at the one place where he wants to play."

Unless LSU is put on probation, Horford would have to sit out a year after he transfers. LSU Coach Dale Brown has denied any wrongdoing in the recruitment of Horford.

Under NCAA rules, Horford now can be recruited by any school other than Houston. However, as offcampus recruiting is not allowed at this time, schools may only telephone him. He can visit any campus if he pays his way.

Dave Maggard, athletic director at California-Berkeley and chairman of the eligibility subcommittee, said his group believed "the University of Houston had a decided advantage in visiting him in the Dominican Republic during a noncontact period and by providing transportation (for him)."

Maggard said the five-member committee always gives the benefit of doubt to the athlete. In three other cases it also decided this weekend, one involving Houston sprinter Joe DeLoach and the others involving Baylor basketball players Darryl Middleton and Eric Johnson, penalties were reduced.

The decision rendered today in the Horford case focused only on his recruitment by Houston. It did not address recruiting by any other schools (Houston argued that other schools also contacted Horford at the same time) or the yet-to-be answered question of whether his amateur status has been compromised.

The NCAA is investigating whether he received excessive expenses while playing for Club Naco in a Dominican league last summer.

The decision on Horford, whose recruitment is considered one of the most bizarre in NCAA history, overshadowed an 11th-hour effort by the predominantly black schools to sway delegates' opinions on the use of test scores to determine first-year eligiblity.

Sam Myers, president of the National Association for Equal Opportunity in Higher Education (NAFEO), said the leaders of his group had decided that a walkout following Monday's votes to modify Proposition 48 as it appears in the NCAA Manual, "might be counterproductive."

He said that the possibility of fighting the rule in court was "a serious option." But he said NAFEO first would concentrate on swaying public opinion. He said a suit was not prepared to be filed at this time.

Unless modified during Monday afternoon's Division I business session, Proposition 48 would become effective for the upcoming academic year. It calls for a minimum 700 (out of 1,600) on the Scholastic Aptitude Test or 15 (out of 36) on the American College Test and a 2.0 core curriculum in 11 academic courses in high school to be eligible.

"We know we're in a strong position that right is on our side," Myers said. "We have to be extremely careful to maintain dignity and not appear to be petulant."

The predominantly black schools focused today on gaining support for a proposal that would eliminate test scores but keep the core curriculum.

Percy Pierre, president of Prairie View A&M and a former assistant secretary of defense in the Carter administration, said a $200,000 study by the NCAA shows Proposition 48 is discriminatory.

"The heart of the argument is that the express prupose . . . is to increase graduation rates," Pierre said. "What it does is disqualify a large percentage of students who otherwise would have graduated based on the NCAA's own study. It disqualifies black potential graduates at twice the rate it disqualifies white potential graduates."

He said the NCAA study shows 70 percent of black male scholarship athletes entering college in 1977 who actually graduated would have been disqualified under Proposition 48. He said about one-third of white graduates would have been disqualified.

The Southwestern Athletic Conference also has proposed that test scores be used only for placement purposes.

A third proposed modification of Proposition 48 would allow a limited sliding scale for the next two years to allow a higher grade-point average to offset a lower test score. There would be a gradual phase-in until 700 on the SAT and a 2.0 grade-point would become the minimum in 1988-89.

The limited indexing is sponsored by both the NCAA Council and the Presidents Commission, and NCAA officials expect a close roll-call vote but passage of this modification. Still, a group led by Bill Friday, president of the University of North Carolina, opposes any changes in Proposition 48.

The NCAA Council decided to withdraw three of the four proposals that opponents say would deprive members of their rights and would make them take sides against their own athletes in litigation with the NCAA.

Vice President George Bush will receive the NCAA's Theodore Roosevelt Award, its highest honor, at a luncheon here Monday. Bush, an ardent tennis player, captained the Yale baseball team and led it to two second-place finishes in the NCAA tournament.

Among others to be honored are Eddie Robinson, football coach at Grambling State, who has won more football games than any college coach in history; pro golfer Jack Nicklaus; former pro football stars Bob Lilly and Fran Tarkenton; and Jim Dombrowski, all-America tackle at the University of Virginia.