About 406,000 hourly General Motors Corp. workers soon will receive performance bonus payments that average $900 to $1,000 per worker, the automaker says. Distribution of the checks, which total about $307 million, began Thursday, GM said. Each worker receives 3 percent of his or her earnings from the previous year, based on the rate of pay and the number of hours worked. The payments are part of the three-year GM-United Auto Workers union contract that went into effect last year. ``These special payments recognize the relationship between an improved standard of living, technological progress and the cooperative spirit and teamwork attitude of all employees in achieving that program,'' said Alfred Warren Jr., GM's vice president for industrial relations.