Flight Sydney Airport departs from Sydney Sydney Airport at 15:00 and arrives at Melbourne Melbourne Airport at 16:35.
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 Wednesday, as prices are on average 96% higher than on Saturday. (Average prices, based on 36714852 datapoints.)
This graph shows the distribution of prices found in the past years for this flight. (Average prices, based on 101 datapoints.)
We have a lot more statistics for flights QF 455 and between Sydney and Melbourne.