House Democrats shot great clouds of rhetoric at the Reagan administration yesterday, accusing it of a "free-lunch" fiscal policy and a "bunker mentality stemming from a gargantuan sense of egotism" -- but all the while subscribing to most of its basic programs.

Senate Republicans also made it an ambivalent day for the president. The GOP-dominated Senate Budget Committee agreed to make room in its budget resolution for his proposed three-year tax cut. But this led the committee to project a $60 billion deficit for next year, $15 billion more than Reagan is counting on and $10 billion more than even the House Democrats calculate.

The committee indicated, however, it may reduce the deficit later by spending cuts.

Completing a day of confusion at the Capitol, a dozen moderate-to-conservative Senate Democrats winged off in their own direction, endorsing the president's economic goals and spending reductions but calling for a tax cut that it tilted more toward increasing investment and productivity.

The sharpest attack thus far on the administration came from the normally soft-spoken, bland-mannered chairman of the House Budget Committee, Rep. James R. Jones (D-Okla.), who apparently saw red as he heard Vice President Bush, Treasury Secretary Donald Regan and Budget Director David A. Stockman tearing into the Democrats' budget plan on Tuesday night.

"The administration says it can accept no amendments, that its budget is untouchable," said Jones as the committee began its second day by work on the Jones-drafted Democratic alternative to Reagan's budget. "No administration has ever made such demands, and no Congress has ever accepted such demands. It is not the job of the Congress not to think."

Asserting that the administration objects only when Democrats propose changes in its budget, Jones added: "What we are seeing on the part of some administration spokesman is a bunker mentality stemming from a gargantuan sense of egotism."

Rep. Delbert Latta (R-Ohio), ranking Republican on the committee, rushed to the administration's defense, accusing Jones of over-responding out of fear that the Democrats' counteroffense was falling apart just as it started to roll.

Indeed, there did appear to be signs of trouble for the Democrats on both their left and right flanks. Conservative Democrats were objecting to Jones' proposed trade-off of some defense money for social programs, but Rep. Les Aspin (D-Wis.) warned that liberals are likely to resist if the committee adds more for defense to placate the conservatives. Some members of the Congressional Black Caucus were also complaining that Jones does not depart enough from Reagan to satisfy them.

But there were also indications of edginess among Republicans. Trying to explain the Republicans' counterattack, Rep. James G. Martin (R-N.C.) said that, especially with the president hospitalized and temporarily out of action, "we're concerned that the program is starting to unravel."

There were further salvos from the administration, too. Deputy Defense Secretary Frank Carlucci lashed out at Jones' attempt to nibble at the big defense spending increase that the administration wants. He said that Jones' proposed $4.3 billion bite off the top of an overall increase of more than $30 billion for the Pentagon would "serioudly delay our ability to increase the readiness of our forces and rebuild our defense capabilities."

Later in the day, House Democratic leaders unveiled, with much fanfare, their long-awaited "Statement of Democratic Economic Principles," which, while attacking the administration's tax and spending policies, embraced a lot of notions that once would have figured more prominently in a Republican campaign platform.

Even its catchiest phase -- that the administration's idea of stimulating growth and curbing inflation by across-the-board tax cuts amounts to a "fiscal equivalent of faith in a free lunch" -- was borrowed from old GOP campaign rhetoric about old Democratic programs.

The document, endorsed earlier in the day by rank-and-file House Democrats, said the Democrats will support a "national consensus" for slowing federal spending, reducing the size of government and "its maze of regulations" and providing tax relief to offset the effects of inflation.

But, the Democrats asserted, they will not "join in any program of fiscal control that puts the main burden of fighting inflation on the backs of the middle- and low-income workers while providing unprecedented benefits for the privileged few." Nor, they said, will they support "false economies which will result in more spending and higher deficits in future years."

But their priorities included such old GOP standbys as eliminating "fraud, waste and abuse," promoting the "work ethic," strengthening "our defense force," and upgrading "our efforts in the area of law enforcement" as well as the more traditionally Democratic idea of "help[ing] those who cannot work."

"The world today is not the same as it was five or 10 years ago," said Rep. Richard A. Gephardt (D-Mo.), a principal drafter of the statement. "Some [of the statement] is conservative, some is liberal," he added. "But it's different from the Republicans."

Aside from tax and spending priorities, one of the chief differences was support for an "incomes policy" under which the government would try to suppress wage and price increases, which the Reagan administration rejects in favor of free-market discipline.

The Democrats also called for a stronger role for government, in cooperation with business and labor, in the areas of energy development, technological innovation, labor-management relations, suppression of interest rates and what they called "investment in human capital" through health, education and job training programs.

Meanwhile, before voting 12 to 9 along party lines to allow room for Reagan's $51.3 billion tax cut this year, the Senate Budget Committee rejected three separate Democratic tax-cut alternatives. But it approved a proposal calling on the Finance Committee to consider closing unspecified tax loopholes, with savings to be passed on as tax cuts.

The House Budget Committee stuck largely by its proposed Democratic alternative as it worked into the night on the budget. It deviated, however, by reducing revenue sharing for states with severance taxes by $75 million. The proposed budget had cut revenue sharing by $200 million. The committee also rejected, on a tie vote, a move to restore $1.5 billion that Jones proposed to cut from funds for filling the Strategic Petroleum Reserve.