President Carter won some born-again supporters here today, and strengthened the convictions of those who had never lost the faith.

His speech before an estimated 4,000 delegates to the 44th annual convention of the National Association of Counties was a hit.

Even many Republicans in the heavily Republican NACO gave the president generally high marks for his followup remarks to his Sunday night, down-from-the-mountain address.

"He was a different man," said Mary J. Jornlin, Republican county executive from New Castle County, Del. "He was more forceful than I've ever seen him before . . . I still say that he hasn't given us many specifics. But, today, I think he was impressive."

"Before I heard the president Sunday night and this morning, I thought, well, he's a nice man, but he's kind of weak," said Arthur C. Polzin, a Democrat from Saginaw County, Michigan.

"But now, I think he's ready to kick some a--. He realizes that we have to start from somewhere to try to solve these energy problems . . . I think we should support him."

Outgoing NACO President Charlotte Williams of Genesee County, Mich., said: "The president is coming off as being a real leader. I think the county officials and the nation, as a whole, will view him as being very sincere and forceful." She said she blieved NACO would vote to support Carter's energy proposals.

Many convention participants, especially those in NACO's leadership, said they were pleased that the president seems willing to allow them to pay a major role in working to solve the nation's energy problems.

Carter urged the county officials to create their own local energy conservation boards. Francis B. Francois, a Prince George's County, Md., councilman who also is NACO's first vice president, said that efforts to implement Carter's recommendations will place special burdens on local governments.

"He's right when he says we have to stop looking to Washington to solve these problems," Francois said. "What he's asking is going to make our job a lot harder at the local level but this is something that we will just have to bear."

Richard Kelly, a Democrat from Guthrie County, Iowa, said that "it is about time" Americans realized that they, too, are a part of the nation's energy problem.

"I don't think they can blame Carter too much for the energy crisis," said Kelly. "I think the American people, if they can fault him in any way would have to say that his only problem is that he is too honest in describing the situation."

Many convention delegates hailed Carter's call for immediate quotas on the import of foreign oil. They said his decision to "draw the line" on consumption of foreign oil gave them confidence that he finally was going to do something to develop domestic oil production and to explore alternative energy sources.

The only outspoken criticism of Carter's speech here today came from Republican presidential hopefuls. The most biting remarks were made by former Texas governor John Connally, who accused Carter of trying to shift the blame for the nation's energy and economic woes from the White House to the electorate.

"I had great empathy for the president last night and this morning," Connally said. "He was begging.He was pleading. He was begging for protection from his own party, which has shackled him."

Connally's remarks drew enthusiastic applause from the NACO Republican caucus. But several Republicans said privately afterwards that they were embarrassed.

"I think what Mr. Connally was trying to do was to get into the papers," said one Republican county official from Wisconsin, who requested anonymity.