 The VFX's air-to-air missiles would be either six AIM-54 Phoenix or a combination of six AIM-7 Sparrow and four AIM-9 Sidewinder missiles.Bids were received from General Dynamics, Grumman, Ling-Temco-Vought, McDonnell Douglas and North American Rockwell; four bids incorporated variable-geometry wings.McDonnell Douglas and Grumman were selected as finalists in December 1968.