He doesn't belch. He doesn't mooch. His conversation runs more toward Aïda than fish bait. As a matter of fact, if it weren't for that gap-toothed, slightly goofy grin, it would be hard to recognize Randy Quaid as The National Lampoon's Vacation series' Cousin Eddie, the drop-in relative of your darkest dreams. So why is Quaid, elder brother of heartthrob Dennis, continually cast as a geek?

"Well, gosh, uh, well," says Quaid, 39, stretched out on a lounge chair on the back porch of his new Montecito, Calif., home. He modeled Eddie's boorish moves, he explains, after a guy he once worked for at a Baskin-Robbins store. He took the table etiquette from a Quaid family cousin: "Just shovel it in and finish it. No conversation. Just a bunch of eating sounds." Then comes the belly laugh. "You know, I hate to compare myself to Eddie, because he's such a jerk." His wife of two months, Evi Motolanez, 26, seconds the notion. "My nightmare," she says, "is that people are going to see National Lampoon's Christmas Vacation and think, 'That's the guy Evi married.' "

While Christmas Vacation plays across seasonal screens, Quaid's thoughts are on his new marriage—and a recent return to Archer City, Texas. He spent time there this fall filming Texasville, the sequel to Peter Bogdanovich's 1971 The Last Picture Show. Back then, Quaid's character Lester Marlow escorted Cybill Shepherd's high school heartbreaker to an infamous pool party. This time around, he faces financial ruin and romantic turmoil. But off-camera, Quaid reflects on more positive life changes. "Acting's more of a business for me now," he says. "Back then, it had all this glamour. I took my first jet plane ride to do that movie."

Randy had been itching to act ever since he watched his father, Buddy, an electrical contractor who died in 1987, try to imitate the actors he saw on TV. "I'd come home from school," recalls Quaid, "and work on voices in front of the mirror." He polished his act as a drama major at the University of Houston. There he met Bogdanovich, who was holding Picture Show auditions.

Along with co-stars Shepherd, Cloris Leachman and Jeff Bridges, Quaid attracted Hollywood's attention. In the years that followed, he put his mark on a host of quirky characters, from the kleptomaniac sailor in The Last Detail (1973) to this year's suburban cannibal in Parents. On television, a brief stint on Saturday Night Live was followed by such surprising turns as his extraordinary Lyndon Baines Johnson in the 1987 NBC film LBJ: The Early Years.

But while his career was building, Quaid's life was falling apart. "I went through this delayed-adolescence thing,", he says. "I didn't want to be tied down to a family." His five-year marriage to Ella Jolly, a former model, broke up in 1985, and Quaid set out on a three-year dating spree. Then last December, he met Evi on the set of Bloodhounds of Broadway (Madonna's gangster farce, which had a brief release this fall), where she was a production assistant assigned to run errands, make coffee—and drive Randy to and from the set. The first night they went to dinner, Randy told her he loved her. Two weeks later, he proposed. "I was sort of expecting it, actually," Evi says. "It was just so obvious that's where it was going."

Randy's daughter from his first marriage, Amanda, 6, who lives with her mom in Manhattan, spends time with the couple when she can. "I'll always love her, and she'll always love me. That's one thing I know" he says. They talk on the phone regularly, and he's even thinking of buying her a fax machine. "Then she can fax me her homework."

As for his relationship with his brother, Dennis, 35, Randy says any resentment the two harbored against each other is gone—perhaps played out when they co-starred as the battling True West brothers in a 1983 off-Broadway production of the Sam Shepard play. "It was probably more me than him, anyway," Randy admits. "I might have resented it, struggling and then my name opens the door for him. But I got over that a long time ago." "I don't believe there are two brothers in this world who are closer," says their mother, Nita. Recent events seem to back up that rosy maternal view. Randy asked Dennis to serve as best man at his Oct. 5 wedding in Montecito, and the whole family spent Thanksgiving with Dennis and his fiancée, Meg Ryan, in Montana.

Randy's new home preoccupies him now. "I like it here," he says. "I don't have to fight traffic, and it's near some good golf courses." Evi sighs. "I see golf as totally primal," she says. "It's like putting clubs on his back and going out for the kill."

Randy sees it differently. "It's like life," he says. "You start off at the first tee and travel through the course. You have your good holes, your bad holes, and every shot requires your attention." So far, though, he's scoring better than par.

—Cynthia Sanz, Kristina Johnson in Montecito