Flight Sydney Airport departs from Sydney Sydney Airport at 20:00 and arrives at Melbourne Melbourne Airport at 21:35.
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 Saturday and it would be best to avoid Thursday, as prices are on average 102.74% higher than on Saturday. (Average prices, based on 40604670 datapoints.)
We have a lot more statistics for flights QF 493 and between Sydney and Melbourne.