Buoyed by his primary victory in Puerto Rico, George Bush said today that he had become a "truly national candidate" who would be competitive with Ronald Regan even in such conservative southern strongholds as Alabama and Florida.

Bush declared that his win over Sen. Howard H. Baker of Tennessee in Puerto Rico had given his campaign "a big lift" that would have an impact on the Feb. 26 primary in New Hampshire.

On a cross-state day of campaigning, Bush shook hands, squeezed shoulders, smiled frequently, took some mild jabs at reagan's age and President Carter's foreign policy, and generally behaved like a happy and excited winner.

He declined to predict victory in New Hampshire, where he thinks the race is close, but said that if he did win here, he would then win the primaries in Massachusetts and probably in Vermont the following week. If that happens, Bush added, he would be on his way to the Republican presidential nomination.

"You think you've seen me up to now, but wait until I walk into South Carolina having done all those things," Bush said in a automobile intervie en route to Rochester. "I'll be floating. I'll have strings on like one of those ballons. I won't be a big shot about it, but I'll be up."

The South Carolina primary is March 8, the Saturday before the March 11 primaries in Florida, Alabama and Georiga.

The only cloud on Bush's horizon seemed to be an occasional question about stories in the Los Angeles Times and The Washington Post about money his 1970 campaign received from a secret White House fund.

"We have complied with the law . . . I have a totally clear conscience on it," Bush said at a Manchester press conference. "I believe that everything was clearly and properly reported -- and if it wasn't, there was no effort to try to deceive."

In response to a subsequent question about whether his nominaton would hurt Republicans by raising the "Watergate issue," Bush said this would not happen because he had a record of integrity and the American people would be "fair and honorable" in judging him.

Bush stood on the back of a red pick-up truck to deliver a speech at a Manchester automobile agency, in which he said he attached high importance to his final week of campaigning in New Hampshire.

"I'm going to drive down to this finish line as if everything depended on New Hampshire -- and to a degree it does," Bush declared.

Actually, his remaining campaign schedule in New Hampshire is virtually nonexistent, except for a debate Wednesday night in Manchester with six other GOP candidates and another debate Saturday night in Nashua with his major rival, Ronald Regan.

Late today, Bush and Reagan appeared on the same platform for the first time in the campaign in a presentation before the Portsmouth Republican Club involving all seven GOP presidential candidates or their representatives.

Both Reagan and Bush delivered brief, polite summaries of their basic stump speeches and made no reference to one another.

The same could not be said for Nellie Connally, wife of former Texas governor John B. Connally. She took exception to a remark Bush had made on frequent occasions, to the effect that he is only one of the candidates to have met a payroll.

Recounting here husband's long and varied business experience, Nellie Connally declared: "In Texas, we meet a payroll every week."

The candidates' roadshow then moved on to Concord and a forum before the Gun Owners of New Hampshire, where Illinois Rep. John B. Anderson provided most of the excitement.

To the boos of his gun-owning audience, Anderson said: "We license automobiles. What is so wrong about telling the law-abiding public of this country that we will license gunowners?"

Earlier today Bush, who is 55, sought to capitalize on the issue of Regan's age.Without mentioning that Reagan recently became 69, Bush said repeatedly that he himself feels like a 35-year-old ready to serve eight years as president.

Today, at a rally in Nashua, Bush was introduced by Sam Tamposi, in 1976 the Reagan finance chairman in New Hampshire.

"We've all gotten a little older, even Ronald Reagan," Tamposi said.

But in the interview later, Bush, for all his optimism, was not about to discount Reagan. He observed that the former California governor had come back to make a close race of it with President Ford after losing early primaries in 1976, and said that Reagan still had "a lot of latent strength" in the West.

Bush added, however, that he thought Reagan had stayed out of the Puerto Rican primary because he knew he would lose there.