Heartened by signs of taxpayer revolt and dissension within the Carter administration over the affordability of a broad national health insurance program, this American Medical Association ended its 127th annual convention here yesterday said the feeling that, politically, things may be going its way.

Throughout the four-day meeting - in speeches and corridor chat and across town at a rally of more hardline conservative physician groups - the leitmotif was Proposition 13, the successful California referandum issue that many doctors view as resounding vindication of their antigovernment, antiregular philosophy.

"Proposition 13 was a breeze from the West. It's going to make Washington realize that the public is tired of big government and high taxes," exulted Dr. Alex Scott of Junction City, Kan., one of the 266 members of the AMA House of Delegates.

Scott was one of those who persuaded the organization's governing body to tell its leaders to rethink its position on the inevitability of national health insurance and decide, in light of the coming elections, whether the AMA should bother to submit even its own conservative version when the new congress convenes.

Moreoever, the delegates told the AMA Board of Trustees in no uncertain terms that if the trustees want to submit a revised health insurance plan next year, they should give grassroots members full opportunity to debate and approve the proposal at the next meeting in December.

Referring to the AMA's stagnating membership level at a time when the number of American physicians has expanded rapidly, Scott declared that the AMA's stand in favor of some sort of national health insurance "is the single most galvanizing factor among physicians in our home states."

Up to now the AMA's leaders have persuaded reluctant members that the organization needed to have its own national health insurance plan in order to retain any role in the political debate on the issue.

In other action, the AMA gave evidence that it is beginning to face the challenge of controlling medical costs, even if it is not ready to accept most of the measures recommended six months ago by a broad-based, AMA-commissioned group of experts.

Last December, when the National Commission on the Cost of Medical Care issued its report, AMA delegates nearly rejected it outright. This week, they adopted 27 of it 48 specific recommendations, referred others to various committees for study and rejected only three.

One of the departures from traditional AMA policy was the acceptance a somewhat more accomodating view of alternative methods of financing and delivering medical care such as prepaid health plans and salaried groups of doctors. In one such stand, the AMA delegates endorsed the idea that employers should give their employes incentives to shop around for health insurance and make alternative options, like prepaid plans, freely available.

The AMA also went on record in favor of progress to limit hospital bed capacity according to population needs within a given area and of devising ways to convert unneeded hospital beds to other uses, such as hospital care for the dying.