Read my earlier post again please. Ansett B727's cruised at M .8 or .82 (when I was on them anyway), so with the B727 at FL330 there's not much difference in TAS with a DC-9 doing .76 at around FL270/290, particularly as the 9 was already out in front during the climb. Since we're talking about MEL-SYD, the inevitable tailwind would proportionately reduce the speed advantage the Boeing held too. On longer trips the B727 would win, but certainly not MEL-SYD