The United States has drawn up a list of concrete steps designed to signal its determination to bring about policy changes in South Africa's white-minority government, American diplomats said privately here today.

The steps - some monor, some major - were discussed at the just-concluded four-day meeting of American ambassadors to black Africa attended by Andrew Young, the U.S. envoy to the United Nations.

Examples of the measures considered here were the withdrawal of the American military attache, tightening up visa requirements for South Africans, severing links between American and South African intelligence agencies and curtailing Export-Import Bank credits to the Pretoria government.

One American diplomat predicted that an initial group of actions might be announced within a month.

It was not clear here what exactly the United States expects South Africa to do to avoid the punitive measures, or if their application would be automatic if Vorster refuses to give way.

Young is expected to discuss the steps in Lisbon this weekend with Vice President Walter Mondale, who is scheduled to meet South African Prime Minister John Vorster in Vienna May 19.

Any decision to implement the measures - and the mix and timing involved - would depend on the outcome of the Vienna meeting, officials said.

The actions underscore the break with former Secretary of State Henry A. Kissinger's soiuthern Africa policy. Kissinger, agreed in effect, to turn a relatively blind eye toward racial discrimination in South Africa in exchange for South African support for rapid movement toward black-majority rule in Rhodesia and Namibia (Southwest Africa).

Young made it clear again today that he still hopes that South Africa will change its racial policies in its own self-interest. In the past he has pointed to growing American dependence on oil from Nigeria, a militantly anti-South Africa state whose gross national product is expected to exceed South Africa's soon.

In a televised news conference following a meeting with Ivory Coast President Felix Houphouet-Bogny, Young said that he and his host share the view that "dialogue" with South Africa must be maintained to "avoid massive bloodshed of both blacks and whites."

The Ivory Coast, a prosperous pro-Western agricultural state in West Africa, is one of the rare black African states that conducted open talks with South Africa in the past.

Young, who is to address business and student groups in South Africa next week, said, "I think there will always be tension between me and the South zAfrica government as long as the level of injustice is as high as it is."

He called it a "healthy tension ... the result of the commitment I have, and I think is shared by the world, that majority rule is not just necessary but possible."

Most American ambassadors in Africa appeared pleased with the prospect of a tougher policy toward South Africa. One ambassador said privately, "We are all mostly Afro-philes and would like to see a vigorous policy."

As has become his practice in visiting African heads of state, Young proved gracious after emerging from a two-hour discussion and a long lobster, lamb and champagne lunch with the Ivory Coast president.

"We talked of everything from South Africa to Zaire and the question of development generally," Young said. "He did the talking and I did the listening, and I really count it a privilege to sit at his feet and share in his wisdom."

Houphouet-Boigny, one of the leading African moderates, has expressed dismay at the Carter administration's caution in running to Zaire's aid in March when its mining province, Shaba, was invaded by Angola-based Katangan isurgents.

Convinced that Soviet-Cuban expansionism is a danger to their survival, the moderates have registered incomprehension at some of young's stands, which tended to discount the Communist threat in Africa.

Young told questioners today that much of his countroversial reputation since taking over at the United Nations is due to the American press. "The American press does not understand the significant change in foreign policy taking place under President Carter and Secretary of State [Cyrus] Vance." He said the [WORD ILLEGIBLE] Vance." He said the [WORD ILLEGIBLE] "mindset" is still influenced by the Ford administration.

He defended American policy in Zaire, saying, "I don't think it's the U.S. business to solve African problems than having us come in with the 101st Airborne," he said.

Reuter reported the following developments in southern African:

Informed sources in Johannesburg said that South African wants he scheduled date for Ambassador Young's visit changed from May 21, as announced Wednesday by the State Department, to some time after May 23.

South Africa reportedly does not want Young to be in the country when Prime Minister Vorster will be away for his meeting with Vice President Mondale.

Meanwhile, Transkei proposed a sweeping new security bill designed to supplant securtiy legislation carried over from South Africa, which gave the black enclave independence last October.