Former attorney general Griffin B. Bell yesterday became the second former high official of the Carter administration to testify in support of Judge Robert H. Bork's nomination to the Supreme Court, saying that although Bork is a conservative, "he's principled and rational . . . not a radical."

"I don't think he'd wear anyone's collar. He's searching and growing all the time," Bell said as the Senate Judiciary Committee began its third week of hearings on the Bork nomination.

Lloyd Cutler, who served as White House counsel during the Carter administration, testified last week in favor of the Bork nomination.

Chairman Joseph R. Biden Jr. (D-Del.) said yesterday the committee may complete hearing public testimony as early as Wednesday. But he added that the committee vote on Bork will not be held until at least Oct. 6, almost a week beyond the original Oct. 1 target date, because members have asked for time to consider the deeply divided views of academics, lawyers and civil rights leaders who have testified in the hearings.

After the committee vote, Bork faces a lengthy debate on the Senate floor. That means the Supreme Court will open its fall term next Monday with eight members.

The nomination was harshly criticized yesterday by Philip Kurland, a University of Chicago Law School professor and a former colleague of Bork's, who said it would "help effect the constitutional revolution that has been part of the Reagan platform since he entered office. The claim that Bork is a middle-of-the-road jurist . . . was an afterthought and without much, if any, basis in fact." Kurland is a conservative, but has served as an adviser to committee Democrats.

Bork was also criticized by former senator Thomas F. Eagleton (D-Mo.), who accused him of favoring an "overwhelmingly powerful executive -- the second coming of George III," an allusion to the English king whose authoritarian treatment of his colonial subjects led to the American Revolution.

"When it's a dispute between the president and the Congress, as far as Judge Bork is concerned, the president is always right and Congress should always be deprived of its power to challenge him in court -- even on matters of deep institutional conflict," said Eagleton, now a professor at Washington University in St Louis. "Judge Bork believes not only in an all-powerful president, but in an omnipotent president."

Jewel LaFontant, who served under Bork in 1973 as the first black female deputy solicitor general, praised the nomination and described Bork's help to her when she was confronted with departmental sexism. "I sincerely believe he is devoid of racial prejudice or I wouldn't be here. As a woman, as a black woman, I have no fear of trusting my rights and privileges to Robert Bork," she said.

But Bork was criticized by the Rev. Kenneth Dean of the First Baptist Church of Rochester, N.Y., who said that two years ago Bork made a comment showing he was insensitive to the religious beliefs of a young Jewish boy.

Dean said that at a 1985 meeting at the Brookings Institution here, he described to Bork a situation that he encountered in 1961 as a public school teacher when he was told by a 13-year-old Jewish student that his parents did not want him to participate in required classroom religious readings. Dean said he excused the boy, who was the only non-Christian in the class.

Dean said that when he related the incident to Bork, Bork replied, referring to the boy, "Well, I suppose he got over it, didn't he?"

Bork told the committee earlier that he never made such a remark. Dean said he did not consider the comment anti-Semitic, but he said he was "shocked" by it and believes it "reflected a repressed facet of {Bork's} personality."

Meanwhile, public opinion polls, including a recent Washington Post-ABC News poll, that show growing public opposition to the Bork nomination were sharply criticized at the hearing.

"If we pick Supreme Court justices by what the people want, we are going to be in bad shape," Bell said.

"The Senate ought to rise above all this," he said. "It's one of the worst things going on in this country. People don't know as much {about Bork} as the committee."

Biden reassured the committee members that the vote will be taken "on the strength of the testimony."