Well, apparently in March of 1963, McDonnell had tried to interest the Royal Australian Air Force (RAAF) in a version of the F-4C (Model 98DX) powered by a pair of French-built SNECMA Atar 9 turbojets. This engine was picked because it powered the Dassault Mirage IIIO fighters that were already being flown by the RAAF. However, the RAAF opted instead for the General Dynamics F-111C.