Hungary's leadership changes may boost Gorbachev reforms. But East-bloc neighbors are cool to Budapest's political sweep

``Our conference is of significance not only for Hungary but for the socialist world at large,'' said Karoly Grosz in a television interview following his election on Sunday as leader of Hungary's reform-minded Communist Party. The open conduct and results of the three-day party conference last weekend support his claim. The conference provided a clean sweep of the more orthodox members of the party apparatus controlled for the past three decades by Janos Kadar.

The party conference thus opened the door to a new, more radical stage in Hungarian reform. It also may be seen as a boost for Soviet leader Mikhail Gorbachev, who faces his own crucial party conference in June.

Soviet interest in this conference was evident in the flock of Soviet journalists who covered it and the ``experts'' from the Soviet party apparatus who closely followed the debates, the way the conference was run, and the results.

The scale of the ouster of Mr. Kadar's majority in the party's ruling bodies surprised even the most ardent Grosz supporters. The ``takeover'' was graphically illustrated by Magyar Nemzet, the paper of the party's mass umbrella organization, the Patriotic People's Front. On the same page that it listed the new leadership, the paper reproduced a drawing by a Hungarian artist showing a man wielding a scythe in a wind-swept field.

``It was an earthquake,'' a senior official said. ``No one, in their best hopes, had expected results like this.''

The Soviet Communist Party daily Pravda carried a front page picture of Mr. Grosz with a eulogistic biography. But the ``shock waves'' registered differently in East European countries, some of which distrust Gorbachev-style reforms.

East Germany's media coverage focused on Kadar's warnings against overly radical reform which could erode the party's leading role. Mr. Grosz was ignored.

Czechoslovakia's Rude Pravo carried an extensive report from Budapest, but focused on the endeavor to revitalize the reform program of 1968.

Bulgarian coverage was meager, and, as of this writing, Romanian media had ignored the conference altogether.

East Berlin, Prague, and Sofia - whose Todor Zhivkov has been in office longer than Kadar - would doubtless have been content to see the latter carry on.

East European countries also face their own pressures for change. These could be strengthened by the Hungarian example, particularly by the way demands for better leadership finally made themselves felt here.

A profile of the 1,000 delegates involved in the conference suggests the groundswell ``from below'' was decisive. Seven of 13 Politburo members were dropped, and about 36 newcomers were elected to the Central Committee.

The ruling Politburo now includes Rezso Nyers, a former social democrat who ``fathered'' the economic reform of 1968. His return to the top leadership is seen as a reflection of the new leader's determination to put new teeth into the drive for radical economic reform.

Also promoted was Imre Pozsgay, probably the most radical of Hungary's reformers. The average age on the Politburo is 53, which makes it the youngest leadership in the East bloc.

The Hungarians dismiss any suggestion they are creating a ``model'' which others should copy. But, as the new party leader said, they believe the new program represents significantly new concepts of political life in a communist-ruled country, concepts which might well have an impact on others.

Their party has acquired the ``new voices and new faces'' demanded by one of the delegates, to the evident satisfaction of a big conference majority. If now carries through with the ``new actions'' the delegates also demanded, it would be surprising if the side-effects were not felt beyond its own borders.