There were indications here today that Panamanian strongman Gen. Omar Torrijos is willing to consider modest changes in the Panama Canal treaties that could substantially improve their chances for ratification by the Senate.

Until now, Torrijos has insisted he will not accept any changes. But diplomats who have followed the gnereal's career say he is known for his abrupt reversals of past positions.

Torrijos spent five hours last night and apparently much of today with aides at his beach house 40 minutes by air from Panama City. Informed sources here speculated that Torrijos was talking about possible modifications.

An editorial today in a popular tabloid known to respond to goverment guidance reinforced the impression that compromise is in the offing. Under the headline, "I am not Dogmatic, Gentlemen of the Senate," the editorial emphasized Torrijos flexibility and said some senators had "reasonable objections" to the treaties.

Sen. Howard H. Baker Jr. (R-Tenn.) told Torrijos yesterday that the treaties could not pass the Senate by the necessary two-thirds majority without some changes.

The Senate Minority leader said that in discussing one possible modification to the treaty, Torrijos and his senior treaty negotiator indicated they might be able to go along with it.

As described by Baker, this would involve using the language of a communique issued Oct. 14 by Torrijos and President Carter as an addendum or understanding to the treaties that could be voted on by the Senate and formally approved by Panama.

That communique contained interpretations of the treaties explicitly stating that the United States would retain a permanent right to use military force to defend the canal after it is turned over to Panamanian control, and that U.S. warships would be given priority to pass quickly through the canal in an emergency.

Both points are important to a substantial number of U.S. senators. Baker has indicated here that if this language can be formally incorporated in the ratification process he would be inclined to vote for the pacts.

Until his visit here this week, Baker had not indicated how he might vote.

His role in the closely divided Senate has been regarded as crucial.

Torrijos indicated to Baker, the senator said, that since he had read the text of his communique with Carter to his countrymen in a televised speech a few days before they voted two-to-one to endorse the treaties, he considered this language to be part of the original agreements.

Baker said it was "my clear impression" that Torrijos was willing to use that language in some sort of reservation or understanding.

Another possible modification to the treaties that informed sources here believe Torrijos might accept would be the elimination of Article XII. This gives the United States the right to build a new sea-level canal in Panama in return for a promise that Americans will not build a new canal in any other Central American country.

This provision has concerned a number of senators, particularly Dick Stone (D-Fla.) and Robert P. Griffin (R-Mich.). It was hastily added to the treaty last fall after President Carter spoke favorably of the idea at a "town meeting" in Yazoo, Miss, July 21. U.S. officials say Carter was apparently persuaded of the merits of this proposal by its leading advocate, Sen. Mike Gravel (D-Alaska).

Sources here say this article was never popular among Panamanians because it appeared to give the United States a new opportunity to impose its wishes on Panama unilaterally.

Moreover, Panamanian and American officials here express skepticism that the United States will ever make the enormous investment in a new, larger canal. And if this skepticism were to prove unjustified, numerous studies have concluded that Panama offers the only attractive route for such a canal.

These possible changes in the original treaties could jeopardize the validity of the October referendum here that endorsed the original treaties.

Panamanians and U.S. officials here both say Torrijos will resist changes so substantial that he would have to refer them again to be electorate. A new plebiscite would cost his government about $500,000 and would offer Torrijos' otherwise-silenced opponents a gratuitous opportunity to challenged his one-man rule.

If Panamanians perceived that American pressure could force Torrijos into a second plebiscite, this would be a serious blow.

But well-placed sources here suggest that Torrijos might accept these modifications without a new plebiscite. He told Baker that no plebiscite would be required to incorporate the language of the Carter Torrijos communique in some sort of understanding.

The Panamanians take the view that because Torrijos publicly announced that language before the first plebiscite, there would be no need to vote on it again.

It is not known how many senators' votes might change if these modifications were accepted. However, they might well change the atmosphere significantly.

Torrijos may explain his attitude toward possible modifications Saturday when he is scheduled to meet again with Baker and his two traveling companions. Sens. John Chafee (R-RL/ and Jake Garn (R-Utah).

The sea-level canal issue could be trickier, since it would involve dropping an article from a treaty Panamanians have already endorsed. But some U.S. officials here believe Torrijos could also avoid a new plebiscite on that issue, if only because the provision has no friends here anyway.

Baker has not said explicity that changes of this kind in the treaties would convert him into an advocate of Senate approval. But he has suggested both to reporters and American diplomats here that this might well happen.