The Rev. Jerry Falwell is back in Penthouse magazine and furious about it.

But publisher Bob Guccione is counting on the fully clothed, paunchy Baptist minister to do what voluptuous nude women usually do: sell his magazine.

"The kind of information that we're getting on the Falwell organization is the kind of thing you would expect to pull out of a sewer," Guccione said yesterday. "If Falwell at any time thinks we are taking advantage of the truth, let him sue us."

That is exactly what Falwell did last February after Penthouse published an interview with him in its March issue -- sandwiched between photos of naked women. Penthouse sold an extra 200,000 copies that month. And an angry Falwell filed an unsuccessful $50 million damage suit against the magazine.

Yesterday, Penthouse was back with more on the Lynchburg, Va., preacher. It placed full-page ads in more than 30 newspapers around the country, including The Washington Post, promoting the first in a continuing six-part series of articles on Falwell. The ads pictures the Moral Majority founder -- smiling and arms outstretched -- beneath this headline: "He may not be Pet of the Month but he's uncovered in this issue of Penthouse."

"It's no more than one would expect from a porn king upset with a preacher who is working hard to put him out of business," Falwell said yesterday. "It's the kind of cheap, innuendo-type journalism you would expect from Penthouse."

In his suit earlier this year, Falwell claimed the interview had been obtained by two free-lance writers who had not told him they planned to sell it to Penthouse and had caused him irreparable harm among his followers. A federal judge dismissed that suit last August, saying Falwell had failed to prove damages.

"Money is no object as far as the war on Falwell is concerned," said Guccione, who says he has spent nearly $500,000 on the investigation he commissioned days after Falwell sued him. Guccione said a forthcoming article is entitled "The Child Victims of the Moral Majority."

"Of course, I'm out to sell magazines. Jerry Falwell is of great interest because we made him that way," said Guccione, who designed the ad that ran in newspapers from Los Angeles to Richmond. "As you know, Penthouse specializes in investigative journalism. We're not doing this series exclusively or even partly because it is a big hype for magazine sales."

The Penthouse story, which calls Falwell "just another of God's many Barnums," consists of information about Falwell's business deals that has been reported previously in several publications, including The Washington Post.

The article, written by free-lancers L.J. Davis and Ernest Volkman, is subtitled "If a businessman is to be judged by the company he keeps, then Jerry Falwell may have a lot of explaining to do." It focuses on Falwell's relationship with the late F. William Menge, a Lynchburg businessman and former member of the board of Falwell's "Old Time Gospel Hour." Menge used his association with Falwell to arrange nearly $9 million in loans on which he later defaulted.

In l978, Falwell has said, when he learned that Menge was improperly using his connection with Falwell, he was voted off the Gospel Hour board. In September l980, Menge was decapitated when he fell from his tractor. The coroner ruled the death an accident.

"The entire article makes not one accusation against me or the ministry," Falwell said. "It's very carefully worded. I'm sure his attorneys read every word 100 times.

"The fact that he had to pick on a dead man whose widow and little children live in Lynchburg, tells you what kind of man he Guccione is. They're riding this horse to death."

"We're not picking on a dead man," said Guccione, who said Penthouse's future stories on Falwell would focus on "people who are very much alive."

Guccione said he does not know how well the current issue is selling, but if Lynchburg is any indication, he need not worry. The manager of one newsstand said that as far back as August, some of the city's most prominent residents were calling to put their names on a waiting list that eventually included more than 50 names.

"It's selling pretty well," said the manager, who requested anonymity. "Let's just say a lot of people are talking about it."