By Howard G. Chua-Eoan

I was into racing trucks," says ex-adventurist John Clark Gable, 27, only child of Clark Gable and his fifth wife Kay. "I've grown up a lot." Now he's ready for Dad's line of work, and will star in the western Bad Jim, which comes out this year, the 50th anniversary of Gone With the Wind. His daughter Kayley, 2, is boning up on the family trade too. "When we watch Rhett Butler," says her mother Tracy, "she says, `There's Grandpa Gable.'"