Irvin Kiffin is 27 years old, a 6-foot-9 starting forward and leading scorer for Athletes in Action, an amateur basketball team made up of Christian missionaries.

Kiffin is married, has a 2-year-old daughter and draws nothing like an NBA salary. His scholarship from the Campus Crusade for Christ nets him $10,000 a year plus approximately $100 a month for the care of daughter Chauniqua.

That kind of money would not be enough to support the $50-a-day heroin habit he fed as a youngster in the bleak street of New York.

"I smoked marijuana at 12, sniffed heroin at 15, and started shooting up soon after that," said Kiffin who grew up in a tough, black section of Queens. "I shot up three time a day so I needed six or seven bags. That was a good day. Sometimes I could only get four bags.

"I was very involved in what may peers thought. And they were shooting dope."

Like most adolescent addicts. Kiffin stole typewriters, television sets, "anything I could pawn, from anybody," and drugs when he should have been in school.

He twice dropped out of Virginia Union College, where he was on a basketball scholarship and shooting hoose - hoose, as in heroin, not the kids' basketball game.

"The second time I dropped out of school," said Kiffin, "was the lowest point in my life."

He went back to New York entered a rehabilitation center, met a wonderful woman and began to kick his habit.

"It took me about a month a kick the physical part to get where there was a day I wouldn't get sick," said Kiffin. "But the mental part, that was hard to kick."

At this point in his life, Kiffin remembers himself as having no goals. My only security was Myra. He married Myra, but almost lost her when he shot up on their wedding night. The next day with things a little smoothed over, they left for Oklahoma Baptist College where he would play basketball with a temmate who would change this life.

"I had kicked my habit, but I always had that fear that when I got back around the fellows, I'd do it again," said Kiffin.

A teammate named Wardell Jeffries introduced Kiffin to Christianity, an event that Kiffin says swept the torture out of his life.

"When I found Jesus Christ, I found all the security I needed," said Kiffin. "That fear - of being around the fellows, getting into it again - was gone I didn't have to worry about hanging out with the fellows.

"A lot of people refer to it (Christianity) as a crutch. If it is, it's the best crutch I know.

"My life has a purpose now to share with other people what I have found and at the same time do the thing I love, play basketball. If I hadn't found Christ, I think I might be back in New York, messing around, in jail, or may be even I'd be dead."

So Kiffin plays basketball for AIA, preaching at halftime, inviting people from the audience to "invite Christ into your lives."

Last night Kiffin and his mates were at Cole Field House to play the Maryland Terrapins.

Some people are rubbed the wrong way be a halftime activity that seeks to save their souls. "Sometimes people won't shut up," Kiffin said.

But this, by all appearances, is a sincere group. Coach Bill Oates estimates that the money AIA makes from the games might not even cover their travelling expenses. Center Ralph Drollinger turned down a three-year no-cut, $400,000 contract with the Nets to draw the AIA single man stip-end of $7,500 a year. When he is asked why, he often quotes the words of Jim Elliot, a missionary killed by natives in South Ameirca. According to Drollinger, Elliot said, "He is no fool who gives up what he cannot keep to gain what he cannot lose."

There is no rule against defecting to the pros, and a player on last year's AIA team, Alonzo Bradley left for the Houston Rockets with the team's blessing.

Four new players on this year's team were drafted by the NBA, including Georgetown graduate Derrick Jackson, who has explained to skeptical questioners that AIA is not a halfway house between college and the pros for fourth-round picks like himself, who are recovering form ulcers.

"What I'm doing," said Jackson, "Is much more important (than earning money in the pros.)"

The team usually plays colleges, tours from August through March. Plays its home games in Anaheim (Clif.) Convention Center and is so good (130-20 in Oates' previous three season) that some schools, including Notre Dame, refuse to reschedule AIA.

This draws a chuckle from public relations man Joe Smalley, who says, "The Christians are playing the lions, and the Christians are winning."

Because the players are not salaried, but are receiving scholarships, they maintain their amateur status and are increasingly called upon to represent the U.S. in tournaments. Smalley says that from the AIA's 12 teams in nine sports, "we hope to place 30 to 50 athletes in the 1980 Olympics. We feel that is a realistic goal.

AIA fields three basketball teams: AIA-USA, AIA-Canada and AIA women's squad. There also are teams in wrestling, weight lifting, cross country, track, volleyball (men's and women's), fast pitch softball, soccer and gymnastics.

AIA players to win - a practice pray some people find offensive.

But Kiffin explains. "We pray to glorify God, and you can glorify God in a loss. But people are more anxious to listen to winners. It makes them sit down at halftime."