For most of the faithful, attending the 8 a.m. Sunday service at the Church on the Rock means driving into a blinding Texas sunrise. But they still can make out the bold message on big billboards along the highway out of Dallas: "Pastor Larry Lea Presents . . . JESUS!"

Lea's services -- four on Sunday and one on Wednesday night, which he calls "pep rallies" for Jesus and "mass counseling" -- are as unabashed as the billboards. They blend the soul of a black Gospel revival, the casual warmth of a small-town Kiwanis Club lunch, the energy and decibel level of a rock concert and the emotional release of group psychotherapy.

"Some people don't believe it's right to have fun in church," he said, interrupting his humor-laced sermon with a stage-whispered aside. FUNDAMENTALISM THE NEW OLD-TIME RELIGION --------- "I believe church ought to be like life is."

This church, like its counterparts across the land, offers a kind of one-stop spiritual shopping bazaar to meet the changing needs of a hungry flock.

On the cutting edge of this change are the waves of upwardly mobile working people. Often they are those who have made the leap from a rural past toward the new cities of the southern "rim," where the jobs are -- a crescent from eastern Virginia to southern California. They pack their old-time religion with their dishes, according to social and religious analysts.

Much of the foment and impetus for political activism that has put conservative Christianity in the limelight is said to come from this "transitional" generation.

Their home turf tends to be on the edge of town, in the suburbs, geographically and symbolically bridging the gap between the country and the city, according to Michael Lienesch, a political science professor at the University of North Carolina at Chapel Hill who is writing a book on the religious right. Searching for community and, some say, authority, they swell the new independent churches run by charismatic preachers who, he says, serve as "father-figure, shepherd, educator, friend -- and who answer to no one.

"They are coming into contact with the whole wider post-industrial urbanized sectarian world, and it can be terrifying."

Barry Hager, an official of People for the American Way, established by television producer Norman Lear to counter the conservative forces of the Moral Majority, said, "They've got about as many polo shirts on their side as we have on ours. They have some fairly Yuppy-ish kind of folks. "Conservative Churches Gaining Members

While mainline Protestant and other churches have lost members in recent decades, conservative Christian ministries have been holding theirs, particularly the young. In some cases, they have seen explosive growth in membership.

The Church on the Rock, started by 13 families in the back of the Skateland skating rink (they dubbed themselves "holy rollers") four years ago, now has 6,000 members and still is growing.

Said to be one of the fastest-growing congregations in the country, it combines a number of the strands of faith and style that form the fabric of the Christian right. Although each church is different, this one offers as good an example as any of the dynamics at the grass roots.

"I tell people I go to an interdenominational, charismatic, Pentecostal, evangelical, fundamentalist, 1st-century Bible church," said history teacher Barbara Montgomery.

Pastor Larry, as he is known, takes up the collection in an old work boot, which came to him when a member stuffed it full of cash as a church donation. He paid for the $1.4 million church complex, about 25 miles east of Dallas, in cash -- supplied "by the boot."

In the service of the Lord, Lea and gathering waves of preachers like him, classic entrepreneurs, have put modern marketing technology into harness with a theatrical appeal that Madison Avenue might envy. Particularly in Texas, conservative Christianity walks comfortably hand in hand with the capitalist ethos of bigness, growth and success.

In the parking lot at the Church on the Rock, the relatively new Buicks, Chevettes and Toyotas far outnumber the pickups and big old clunkers. Inside, there is as much silk and wool as polyester and flour-sack, and a sprinkling of jeans and sneakers. A woman complains about the high price of her Giorgio perfume.

In the lobby is a big National Geographic map of "The Political World." For sale on long tables are Christmas toys made by Praise Unlimited, the "premier Christian toy company." One set called the "Full Armor of God" ($24) includes a plastic helmet, breastplate, shinguard straps and sword, based on Ephesians 6:10-17.

Before the Nov. 6 elections, stacks of voter registration cards greeted members in the lobby.

Inside, Lea preaches his own blend of fundamentalist doctrine and evangelical zeal laced with a charismatic's belief in modern miracles, prophecy, faith healing and speaking in tongues.

The son of a well-to-do Kilgore, Tex., family, Lea had established something of a reputation as a "good pulpit man" in Southern Baptist churches before going out on his own as a traveling evangelist. One night he had been invited to hold a Bible study group in a home in Rockwall, he said in an interview, and afterward, this place "began to haunt me . . . . The Lord spoke distinctly in my heart and said, 'Go to Rockwall.' "

The mood of his services is of contagious joy and comfort.

Lea is backed by a 12-piece band, including a grand piano and a brass ensemble, with a dozen microphones scattered around and four big speakers over the stage.

As the music swells, the standing room-only crowd -- mostly white but with a scattering of black and Hispanic faces -- does more than just sing. Many people raise their hands in the air and keep them there, some smiling blissfully, crying out "Amen" or "Praise the Lord," as the spirit moves them. Some speak in spontaneous bursts of unintelligible phrases.

After the songs, they applaud or, as the pastor puts it, "give the Lord a hand."

Each person carries a well-thumbed Bible. Some are leather-bound and monogrammed, some disintegrating paperbacks.

Between songs, Lea, 33, a personable man with wavy brown hair and a boyish grin, ignoring his almost-invisible Plexiglas pulpit, prowls the stage with a cordless mike, exhorting his flock to accept Jesus, to be water-baptized if they haven't been, telling stories of modern miracles, calling people in the crowd by name, joking with them.

An all-state golfer as a youth, Lea says he plays racquetball three times a week to maintain the stamina he needs to do six services each week.

He calls on God to remove tumors and other sicknesses, and cites a man, with a name and details, in whom he believes such intervention has happened in the last week or two.

"The Holy Spirit's a gentleman, he's not going to hurt you. Don't blow this moment," he shouts, as the music rises again. "You say, I'll think about that and catch it later, down the road. Well, down the road done took off!"

A number of people rise from their folding chairs and come forward, to a waiting phalanx of associate pastors and counselors. Some join the church, some ask for healing or guidance for themselves or a friend. They pray together.

The service ends with a roof-raising collective shout of "Hallelujah!"

Lea doesn't have his own TV show, preferring instead a "hands-on, eyes-on" ministry. "You'll never build a strong local church," he said, "if your emphasis is television."

"I used to go to church out of duty. There was no excitement. Oh, the people were lovely people who believe in the Lord but it just seemed routine," said John Davis, a young Rockwall high school science teacher and football coach. He and his wife left a Baptist church to become members of the nondenominational Church on the Rock.

"Now I look forward to going and, if I have to miss, I get a tape," he said. Tapes of Lea's services are on sale in the church bookstore. TV Preachers 'Too Sophisticated'

Lienesch distinguishes the proclivities of the newly activist conservative Christians from those who retain a more traditional Bible Belt bent.

Jerry Falwell, Pat Robertson and other politically active electronic preachers "have surprisingly little following in small rural communities," he said. "The reason? In many ways the TV preachers are much too sophisticated for those people. They don't need Jerry Falwell. They've got a church they've belonged to for generations . . . ."

The newly activist conservative Christians are likely to have at least some college education. They are the work force of the low- and middle-income service and high-tech industries. They program computers, type on word processors, serve as engineers in nuclear parts and helicopter plants, sell real estate and cosmetics, provide investment counseling. Some are doctors or dentists.

"They made it big in America at a time when in their view America was rapidly disappearing. They've pulled themselves up . . . and just when they get there, it's all going to hell. They're mad, and they blame liberals, whom they tend to lump into one great conspiracy," said Dennis Owen, an assistant professor of religion at the University of Florida in Gainesville and coauthor of "The New Religious Political Right in America."

These new arrivals also may bring with them "all kinds of baggage" from a life where "they didn't have to be concerned about the social and political fallout of their beliefs," he added. "When you're powerless, you can consign everybody to hell and nobody much cares."

As they look at modern society and what it is becoming, conservative Christians see a battle raging between their "God-centered" morality and the forces of what they call "secular humanism," which is in their view a "man-centered" moral system where right and wrong mingle in the lazy rivers of personal expediency.

Some critics see in fundamentalist thought a reflection of a deep-seated anti-intellectual strain in the American psyche. Even some of their staunchest defenders concede that the most dangerous thing about the aroused activism of the conservative Christians is their potential for narrow-minded exclusion of all who do not agree with them, or what one religious scholar called a kind of "totalitarian impulse."

Their defenders say that they are just taking their turn in the democratic process along with everyone else, that they are protesting as best they can the headlong rush of the 20th century and the loss of control by ordinary people in favor of an elite that includes college professors, scientists, politicians, media pundits and large bureaucracies.

In one sense, fundamentalist Christians are "people who seek simple, absolute answers to complex problems as a way of dealing with their intolerance for ambiguity," said Bill Martin, a religious scholar and sociologist at Rice University. "But the problems they are concerned about are real problems that make a great many people uncomfortable who are not fundamentalists . . . . I may cluck when the fundamentalists fight pornography, but I support the consequences. A lot of us have let them do our dirty work for us."

The churches and the electronic preachers, specialists suggest, serve a function of assimilation, helping the transitional pilgrims fit into the modern world while also protecting them.

For those who seek it, conservative Christianity provides extensive sanctuary from the secular world, in the form of Christian schools and a range of social, athletic and other programs.

In the Puritan tradition, the movement incorporates a self-conscious and guilt-free fascination with material success, which its members consider a sign of God's blessing.

The Dallas Morning News reported last year on an array of new linkages between success in the city's business circles, including professional athletics, and the proper religious affiliation. For example, in the booming land development and financial industry here, a "God Squad" of born-again Christian businessmen tends to operate mostly in northern Dallas, while others who are less fervent concentrate in other areas, with the LBJ Freeway as a sort of "Mason-Dixon line."

The born-again businessmen "start their day with a prayer meeting in their office, and they are big on Christian motivational tapes," one young real estate investor said.

"It is not unusual for them to want to pray over a contract before completing a deal," he said, adding that they still can be tough as nails.

Supporting the right Christian charity is a status symbol, he said, and businessmen can be ruthless in the cause. "They are great guys, but when they are sharking for God, they are so dogmatic. There is no gray on anything."

Oil and silver multimillionaire Nelson Bunker Hunt was tapped to raise a billion dollars for one ambitious evangelistic effort. Industrialist T. Cullen Davis became a born-again Christian and created a stir by smashing, at the urging of evangelist James Robison, and throwing into a lake art objects worth $1 million on the grounds that they were "graven images."

With conservative Christians' upward mobility has come a new sense of crisis, said David Edwin Harrell Jr., a history professor at the University of Arkansas who has studied the movement. While they are appalled by the wickedness of American society, he said, they also sense for the first time that they have the power to influence it.

"In short, the fundamentalist vanguard is not so much a frustrated middle class which is losing control as it is an emerging middle class flaunting its newly acquired respectability and power," Harrell said.

"What it is most important to understand about these people is that they are not bigots," said William Murchison, associate editor of The Dallas Morning News and a high-church Episcopalian. "They are not narrow-minded rednecks. They are decent, concerned people who take a broader view of the world than they are usually given credit for.

"They are seeking to work their own salvation and to give salvation to those who know it not," he said. "They are not to be feared. They are not ayatollahs." NEXT: Growth and Dissension