Revenue and income after taxes from continuing operations of San Francisco-based McKesson Corp. set new highs in the third fiscal quarter and nine months ended Dec. 31. Results were restated to reflect the discontinuance of the company's chemical business. Third-quarter revenue was up 17%. After-tax income from continuing operations rose 66%, with fully diluted earnings per share up 54%. Operating profit in the year-earlier third-quarter period was exceptionally strong, a spokesman said. "At the same time, we are experiencing competitive pressures in a number of markets," he added.