More than 300 new churches of various denominations started up during 1986 and 1987 with "instant" congregations already larger than the average Protestant church in America.

And they all started with a telephone call. Well, more like 20,000 phone calls.

By following up 20,000 phone calls with mailings and a final call, most new church efforts will wind up with about 200 people at the initial Sunday service, said Norman Whan, a telemarketing businessman who is now director of church planting for Friends Church Southwest in Whittier, Calif., an evangelical branch of Quakerism.

That first service has a congregation of strangers, assessing each other and their rented facilities, often a school auditorium. On the next Sunday, the attendance is about half, Whan said.

But even with 100 worshipers who stay interested, the congregation is already large enough to support a pastor and a small church budget, by most standards.

Moreover, that is a bigger worship service than that enjoyed by most U.S. Protestant churches. "Fifty percent have 75 people or less in attendance," said the Rev. C. Peter Wagner, a Fuller Theological Seminary professor who heads the Charles Fuller Institute of Evangelism and Church Growth.

The institute has given Whan's technique a wide exposure -- more than 50 denominations have already tried his "The Phone's for You" project.

Wagner said that he had intended to keep the institute's teaching at the level of principles and theory of church growth, and not describe specific methods.

"That was until Norm Whan came over the horizon," Wagner said. "This guy's a winner. We broke our precedent and now highly recommend this technique for planting churches. I haven't had a single bad report."

Wagner said that the general rule of thumb for starting new churches had been to get 50 to 100 people together during four to six months before going public and inviting others to the fledgling church.

"What Norm has done is to cut that time in half," Wagner said.

Whan's experiment in applying telemarketing to new church development began when he and three colleagues started a church in Upland, Calif., for his own Quaker denomination.

Mountain View Friends Church in Upland had its first service on Feb. 26, 1986, with 261 people in attendance. "That church now has about 150 attending and it's completely self-supporting," Whan said. "It meets in a high school auditorium, but it owns five acres of property."

For the Upland church, 20,000 calls were made to people in the area. "From our research we knew that about 2,000 'unchurched' people would be willing to receive information," Whan said.

The initial phone call is supposed to last 45 seconds or less, Whan said. It consists of only one or two questions: Are you now actively involved in a local church? If not, would you like to receive information on a new church? Five mailings and final calls follow during a four-week period.

Whan said the "1 percent rule" -- 20,000 calls resulting in 200 people at the first service -- has not worked every time. "But we believe we have less than a 10 percent failure rate," Whan said. "And what if a church gets only 100 people at the start? Failure is a tough term to define."

He encountered a lot of skepticism at first.

"Many felt it was too cold, not emotional enough. They would ask, 'Where is your leadership coming from?' " he said.

Indeed, Wagner said in an interview that "one of the disadvantages is that you don't know who the leaders and helpers are among these 100 people." Other than the pastor, who is identified in mailings to prospective churchgoers, the leadership is to be determined by the people who stay with the congregation. But Whan said he believes that the absence of a ready-made group of leaders appeals to many people.

The people who come tend to be homogenous in racial, ethnic, cultural and theological terms, he said, because photos of the pastor are in the mailed literature and the beliefs of the sponsoring denomination are outlined.

Whan's own denomination has benefited from the project: Six additional churches were started in Southern California and Arizona using the phones.

The second church started by Whan and his associates was the Desert View Friends Church in Hesperia, Calif. "We did 30,000 dial-ups and had 271 people when it opened," he said.

To start a third church, in Huntington Beach, Calif., Whan hired additional corps of Christian students to make 56,000 calls. Two services were held on opening day for 502 people. "We kind of went crazy with that," Whan said.

Whan estimates that close to 5 million phone calls have been made by church leaders who have followed the recommendations in his $229 manual. As a result, "nearly 50,000 people are coming to church for the first time in a long time," he said.