(http://media.il.edmunds-media.com/mercedes-benz/slk-class/2012/ns/2012_mercedes-benz_slk-class_eng_ns_72111_196.jpg) Mercedes-AMG has developed a new normally aspirated 5.5-liter direct-injection V8 engine that will see its first application in the 2012 Mercedes-Benz SLK55 AMG.