Senate Majority Leader Howard H. Baker Jr. (R-Tenn.) predicted yesterday that President Reagan's lobbying blitz will cause sufficient last-minute vote switches to prevent a congressional veto of the administration's $8.5 billion aircraft deal with Saudi Arabia when the Senate considers the package Wednesday.

Baker, who was interviewed on the television program "Face the Nation" (CBS, WDVM), said he thinks that "soul searching by individual senators and the president's efforts in combination" will give the administration 50 votes. That would produce a tie vote and block adoption of a resolution disapproving the sale of Airborne Warning and Control System (AWACS) planes and other equipment.

Although Baker has been making such predictions for several days, he continued his refusal to give the names and numbers of the senators he expects to switch.

In fact, he denied a CBS news report Saturday that three or four Republican senators had promised him they would change from opposition to support of the Saudi deal.

"I have not said that," Baker said. "I am not the originator of the statement that three or four would switch."

As of now, 52 senators are on record as intending to vote against the deal on the gounds that it poses a danger to Israel or that the sales agreement provides inadequate U.S. control over the AWACS planes. In an effort to reverse the numbers, Reagan plans to talk personally with 18 senators today and tomorrow.

Meanwhile, a coalition of religious leaders calling itself Christians for American Security signed a full-page advertisement in The Washington Post today, calling for the defeat of the arms deal. The group, which includes former Democratic congressman Robert Drinan of Massachusetts and Moral Majority leader Jerry Falwell, called the Saudi regime "anti-American" and said the sale would imperil the safety of Israel.

Two weeks ago, the House voted 301 to 111 against the sale. If the Senate follows the House's lead, it would mean a stinging foreign policy reversal for Reagan and mark the first time that Congess has exercised its prerogative to veto a major arms sale.

Despite their public positions, Baker insisted he knows that some senators, particularly among the Republicans, are still undecided. He asserted: "Some are still in the process of making up their minds, and I believe some will change their minds."

Noting that "my stock in trade is as a counter and persuader," he said that if he wasn't certain that this indecision exists, "I'd be out of business." But, Baker continued, he said he had called Reagan on Saturday and told him, "We can still win."

While insisting that "I'm not going to get into a numbers game," he added: "What am I going to tell you is that the opposition at this moment has less than 50 votes and is losing momentum. Obviously that means that some senators have changed their minds."

Baker conceded that the administration has not obtained any new concessions from the Saudis on the control question, and he denied that the White House has some surprise announcement or maneuver planned in the next couple of days. "Don't look for any bombshells," he said.

Instead, the majority leader argued, he expects various senators to change their positions because of growing awareness that defeat of the package "would cause a devastating blow to the president's ability to manage foreign policy."

In addition, he said, "as people reevaluate the situation, they can see that the pros clearly outweigh the cons."

Baker said he agreed "absolutely" with Reagan's charge Saturday that senators opposing the sale "are not doing their country a service."

He said, "Refusing to sell will begin the unraveling of a policy begun by two administrations to find a consensus" for peace in the Middle East.

The senator said he doesn't believe speculation that a failure to approve the sale would cause an anti-Semitic reaction against American Jews who have been vocal in opposing the deal as a threat to Israel.

No matter how the vote turns out, he said, "there are those of us . . . who would immediately be responsible for seeing that that doesn't happen."

He also denied that a defeat on the AWACS sale would do serious damage to Reagan's efforts to get his budget and economic programs through Congress.

"It won't help," he said, "but I don't think it will have a measurable impact on his leadership ability in economic questions. The issues are too different, and the alliances are too different."