Secretary of State Cyrus R. Vance flies to Seoul today carrying U.S. ideas, but without detailed prescriptions, about the impending political shuffle to replace the assassinated President Park Chung Hee.

The U.S. ideas according to State Department officials, are likely to be couched in terms of Washington's general participation and its opposition to repressive measures.

Asked at a news conference yesterday about a U.S. stand on the 1972 "Yushin" constitution imposed by Park under martial law, Vance said, "We will certainly not be hesitant to express our views when asked on that issue." He said the issue is an important one "being discussed among the Koreans at this point."

The formal purpose of the trip by Vance, who is to be accompanied by President Carter's son Chip and a number of present and former U.S. officials, is to attend funeral rites for the slain Korean leader.During his 26-hour stay in Seoul, Vance also is expected to meet several top Korean governmental leaders.

The crucial questions facing Korea following the end of official mourning late this week are the emergence of a new leader or collective leadership to replace Park, and a means for national participation in the selection or endorsement of the new regime.

Some Korean political forces are believed to favor use of the restrictive 1972 constitution, which provides for election of a president by an easily controlled assemblage of elders, while other forces have made clear their demand for a selection process closer to the U.S. molded mational elections that were jettisoned by Park.

The United States has been critical of the 1972 constitution in the past, saying in February's State Department human rights report, for example, that the constitution withdrew legal rights and that it reduced the influence and independence of the Korean National Assembly.

With many Koreans looking for signs of Washington's attitude as the moment of decision nears, any expression by Vance or other high American officials is likely to be of major importance.

U.S. Ambassador William Gleysteen is reported to have recommended that the United States steer clear of comment on the Korean decision-making process. The State Department's Bureau of East Asian and Pacific Affairs is reported to be urging cautious and very restrained expression.

State's Human Rights Bureau is reported to be pushing for stronger and more explicit expressions of U.S. views and concerns. Carter in the past has backed stronger public and private words on human rights, especially in South Korea, than most of his diplomatic bureaucracy.

A likely possibility, in the view of some State Department officials, is that the current Korean leadership will put forward a plan for passing power which is somewhere between the 1972 constitution and a return to free national elections.

The same officials believe that a compromise national leader, who is acceptable to a broad spectrum of military and civilian leaders and threatening to few, is likely to be proposed initially with a promise of further national decision-making later.

The secretary of state was careful to point out yesterday that the United States has overlapping interests in stability and security as well as democratic processes of the long-term Asian ally. Reading from prepared notes in response to a reporter's question, he said: "We welcome the preservation of stability in this difficult period and hope that future developments will take place in an orderly manner. "We hope that political growth in the Republic of Korea (South Korea) will be commensurate with economic and social progress. "And, as you know, we have reaffirmed our commitment to the security of the Republic of Korea through our statement which was issued earlier this week and through appropriate military action." He referred to redeployment of a U.S. naval task force closer to Korea and dispatch of two airborne early warning aircraft.

North Korea has shown no sign, accorfing to State Department sources, of any impending military action to try to take advantage of the succession crisis in the south.

In one of the most overt maneuvers so far the chandestine "revolutionary party" radio believed to be operated by North Korea, yesterday appealed to South Korean military officers and men to "take the side of the masses and fight gallantly" rather than participate in martial law activities "to maintain the shaky Yushin structure by hook or by crook."