Flight Sydney Airport departs from Sydney Sydney Airport at 14:30 and arrives at Melbourne Melbourne Airport at 16:05.
The flighttime is about 1h 35m. The distance travelled ("as the bird flies"): 787 Km. So the average speed is roughly 497 Km.
The best day to arrive at Sydney is Sunday and it would be best to avoid Saturday, as prices are on average 329.59% higher than on Sunday. (Average prices, based on 36442911 datapoints.)
We have a lot more statistics for flights QF 451 and between Sydney and Melbourne.