The Republic Party set out on its 1980 election year operations yesterday with a record $24.3 million budget and a national poll showing that more voters trust the GOP to handle inflation and budget deficits than think the Democrats can solve those problems.

But Republican National Chairman Bill Brock and Guy Vander Jagt, Republican Congressional Campaign Committee chairman, said that these assets would not translate into a Republican Congress even if the GOP reclaims the presidency in November.

Brock predicted a "significant improvement" in the Republicans' Senate strength and, with Vander Jagt's agreement, said the GOP might gain 25 to 40 seats in the House. A Republican takeover of Congress in 1982 is "clearly achievable," Brock said, but he said "everything would have to go right" for the Republicans to overcome their minority status this year.

Nonetheless, the tone was definitely upbeat as the Republican National Committee met for the first time this year and was briefed on results of a poll taken jointly by Brock and Vander Jagt's committees.

Robert M. Teeter, president of the Detroit polling firm that took the survey, told national committee members that Republicans were even with the Democrats on energy issues, seven points ahead on holding down taxes, eight points ahead on curbing inflation and 17 points ahead on controlling government spending.

In each case, the Republican showing represents a marked improvement for the GOP from its 1974 Watergate low, Teeter said.

The Michigan pollster said the GOP was also in a position to benefit from a growing public awareness of the long Democratic control of Congress and of a public belief that the Congress -- more than the president -- was responsible for many of the problems facing the country.

It was in this context that Brock declared that Republicans "have not had an opportunity like this since 1966 -- and maybe before." In 1966, Republicans gained 47 House seats and three Senate seats.

The budget adopted by the national committee yesterday includes $5 million for a television advertising campaign aimed at fixing the blame for inflation and energy shortages on Democrats. The program is to be introduced next month.

The Republicans also are budgeting $4 million for expenditures to help their presidential candidate and $9.6 million for direct and indirect assistance to candidates at other levels of the ballot, down to the state legislatures.