BUENOS AIRES, Aug 26 (Reuters) - Argentina's automobile production is on course to reach a record 840,000 units this year, spurring investment to expand capacity to 1 million next year, the head of the ADEFA industry group said on Friday. (Reporting by Jorge Otaola; Writing by Helen Popper) ([email protected]; +54 11 4510 2505; Reuters Messaging: [email protected]))