Flight Sydney Airport departs from Sydney Sydney Airport at 17:15 and arrives at Melbourne Melbourne Airport at 18:50.
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 Thursday, as prices are on average 316.25% higher than on Sunday. (Average prices, based on 40610348 datapoints.)
We have a lot more statistics for flights QF 473 and between Sydney and Melbourne.