The nation's Roman Catholic bishops, convinced that they "are on the right track" with last fall's pastoral letter on economics, began strengthening the document here today.

"The positive feedback from around the nation and . . . the world has been the source of much encouragement," said Archbishop Rembert G. Weakland of Milwaukee, chairman of the committee that produced the November document.

Weakland and more than 230 fellow bishops are here to talk about a modified second draft of the pastoral letter, titled "Catholic Social Teaching and the U.S. Economy." The proposed changes include:

* A section linking expansion of the nation's military to such economic issues as unemployment and the availability of funds for human services.

* An emphasis on how the economy affects the family.

* Clarification and reworking of the key section calling for a "preferential option for the poor" -- a phrase originating in contemporary Latin American Catholicism and also favored by Pope John Paul II -- so that "it doesn't suggest an adversarial relationship between the poor and the nonpoor," said Bishop Joseph Sullivan of Brooklyn.

Weakland also indicated he wants to make sure that the bishops' concern for the poor not be interpreted "as an attempt to put the middle class on a kind of guilt trip or blame them for such poverty." He said this was a frequent reaction to the pastoral letter. Local reaction, Page G12.

He said the bishops have "a grave concern for the middle class . . . since the problems the middle class must face are central to where the economic conditions of our times are leading us."

Weakland also promised to reduce the 55,000-word first draft by one third.

He said the final document, a third draft to be completed and approved next year, will also be accompanied by a shorter, more readable "pastoral message" addressed "primarily to our own people."

There also appeared to be a consensus that the letter should address more acutely the church's own economic problems, including hiring practices and investment policies.

"I don't think we will be credible," Weakland said in a news briefing, unless the letter addresses these issues "more than we have in the first draft."

The pastoral letter began as a study of the capitalist system. But it quickly developed into an examination of what the Bible and traditional Catholic social doctrine teach about economic relationships and how to apply these principles to contemporary American life.

The evolution of this pastoral letter, as well as a previous one condemning nuclear warfare, relied on a huge consultative process both in the development of the first draft and the subsequent critiquing of it.

Since its debut in November, the economic pastoral has drawn responses as varied as an academic colloquium at Harvard, a symposium on Wall Street and "stacks of letters," Weakland said, from the poor and unemployed.

Most of the church's 181 dioceses conducted hearings or discussions to determine what grass roots Catholics thought of the document. The bishops elicited this many responses, Weakland said, because they believe that "the Holy Spirit resides in all members of the church and that the hierarchy must listen to what the Spirit is saying to the whole church."