England limped to 144-9 in reply and still have to win a match on their Australian tour after losing the Ashes Test series 5-0 in the first whitewash in 86 years.
Australia's total on Tuesday beat the previous world record held by Ricky Ponting's side of 214-5 against New Zealand in Auckland in February 2005.
Gilchrist's 29-ball innings of 48 included five sixes and two fours and at one stage the free-hitting wicketkeeper-batsman smashed England medium-pacer James Anderson for three consecutive sixes in the sixth over.
Ponting smashed a brisk 47 before a sell-out crowd of 35,628.
Australia warmed up for the tri-series of one-dayers against England and New Zealand by hitting England's bowlers to all parts of the SCG, blasting 14 sixes.
World Cup prospect Cameron White (40 not out) was man of the match. White and Andrew Symonds (39 not out) shared an unbroken stand of 66 in less than six overs for the sixth wicket.
England had a disastrous start to their run chase with Ed Joyce (1) and sacked skipper Andrew Flintoff (0) falling in the first eight balls.
Australian paceman Shane Harwood made the most of his chance at international level, having Flintoff caught at square leg then throwing the stumps down from the third-man boundary to run out Kevin Pietersen for six.
It completed a poor game for Pietersen, who failed to run in to attempt a high catch and then he dropped a simple chance in the final over of Australia's innings.
Captain Michael Vaughan, who missed the Test series with a knee injury, was left to rescue the innings but was lbw to Symonds for 27 at 54 for four.
Jamie Dalrymple with 32 and Paul Nixon's unbeaten 31 added some element of respectability to the innings.
Australia were without injured paceman Brett Lee (chest infection) and Mitchell Johnson (minor abdominal strain) and both will be assessed later this week ahead of Friday's one-day series opener against England in Melbourne.
Australian pace bowling newcomer Ben Hilfenhaus picked up 2-16 including the scalps of Ian Bell for 22 and Paul Collingwood for five in a fine international debut as veteran Glenn McGrath was rested from the match.