Rapped Up in Laughs : Comedy: Chris Rock says he always wanted to do stand-up but ‘lucked into’ acting. He performs at the Coach House tonight.

Reviews for comedian Chris Rock’s rap spoof movie “CB4” have been mixed, but they didn’t stop the musical comedy about three suburban buddies who gain fame by posing as ex-con “gangsta rappers” from being one of the top box-office draws on its opening weekend.

“I can’t really say I’m shocked,” Rock said by phone from New York last week, after the film’s debut the previous weekend in the No. 2 position, behind “Fire in the Sky.” “It’s not as though we opened up against (Arnold) Schwarzenegger or anything.”

Speaking from an office at NBC-TV’s “Saturday Night Live” where he’s been a cast member and writer since 1990, Rock said he slipped in and out of a few theaters on opening night to monitor the public’s reaction to the movie he co-wrote and stars in.

The 26-year-old comic, who headlines at the Coach House in San Juan Capistrano tonight, said it’s too early to gauge the impact the movie may have on his career. And he didn’t have much time to dwell on it, what with a week’s worth of writing and rehearsals for “Saturday Night Live” ahead as well as a string of stand-up performances.

The Coach House show, which will include Tommy Davidson from “In Living Color,” is part of what Rock calls his “HBO special tour.”

He’s squeezing the cross-country tour between episodes of “Saturday Night Live.” It is expected to culminate on Labor Day in Atlanta with the taping of his first solo cable comedy special.

Rock said he has had to curtail his stand-up comedy since joining “Saturday Night Live.” But because the show has just begun a two-weeks on, two-weeks off schedule that will last through the end of the TV season in May, he’ll be able to do at least 50 club and concert dates before taping his special.

Rock, who’s known for his streetwise, politically sharp-edged humor, has been doing stand-up comedy for eight years. When he was about 10, he saw Garrett Morris on “SNL,” and identified with the show’s only black comedian.

“Stand-up’s the thing I always wanted to do; acting was this thing I lucked into,” he said. “Ever since I was little kid, I wanted to do (comedy). Finally, when I was 18, I had the courage.”

The son of a teacher and a newspaper truck driver, Rock grew up in middle-class home in the Bedford-Stuyvesant section of Brooklyn.

“I like to call it the nicest block in the ghetto,” he said. “It’s weird. I can talk about street stuff ‘cause I’m right on it, but far enough removed from it so I didn’t get caught up in it.”

Gangs weren’t a factor when he was growing up, he said. “Basically, either you sell crack or you do crack. There’s none of this red and blue (Crips and Bloods) stuff in New York.”

As for Rock, “I walked the middle,” he said. “I knew people that did both. I still know people that did both.”

Rock received his first national television exposure in 1987 when Eddie Murphy hired him for an HBO special.

Rock, who was only 20 at the time, went straight to his first joke:

“I was driving down the street, I saw a prostitute. Asked her how much. She said, ‘For $300, I’ll do anything you want.’ I said, ‘Paint my house.’ ”

The joke set the tone for his edgy, streetwise act, which includes a routine on blacks who act white (“I bet if somebody told Bryant Gumbel he was black he’d have a heart attack.”), prison overcrowding (“Who (cares)? These guys are prisoners! “) and “Rocky IV” and the improbability of having “two white guys fighting for the heavyweight championship.”

Rock, who once described stand-up comedy as “the blues for people who can’t sing,” said he’s able to generate “big laughs” from such serious topics as abortion and even teen suicide (“a nice, chipper topic; now you know why you’ll never see me on ‘Star Search.’ ”)

“I like talking about things the other guys aren’t talking about,” he said. “Anybody can talk about something that’s already really funny and get a laugh out of that. But to take something totally unfunny--something people feel uncomfortable about--and get a laugh out of that-- then you’re doing something.”

* Chris Rock performs at tonight at 8 at the Coach House, 33157 Camino Capistrano, San Juan Capistrano. $13.50. (714) 496-8930.