Australian Cup winner Super Cool has kept his place at the head of betting for the $2.5 million Caulfield Cup after the release of weights on Wednesday.

The Mark Kavanagh-trained four-year-old has 55kg for the Caulfield Cup (2400m) with Melbourne Cup winner Green Moon topweight on 58kg.

Super Cool moved to favouritism after his first-up third in the Memsie Stakes and remains a $9 favourite on TAB fixed odds Cup board.

Only four horses have won the Caulfield Cup with more than 54.5kg in the past 20 years and Racing Victoria's chief handicapper Greg Carpenter admitted Super Cool faces a challenge.

"The last three-year-old to win the Australian Cup was Saintly (in 1996) and he was allocated 55-1/2 kilos in the Caulfield Cup," Carpenter said.

"He didn't run in the Caulfield Cup but went on to win the Cox Plate and Melbourne Cup.

"The last four-year-old to win with that sort of weight was Sky Heights (in 1999).

"It was an enormously encouraging return from Super Cool in the Memsie, he's got a challenge ahead of him, but he's currently the favourite in pre-post betting."

Green Moon would have to emulate last year's winner Dunaden.

Dunaden won the 2011 Melbourne Cup before returning to win last year's Caulfield Cup with 58kg.

Dunaden is the only original topweight to win the Caulfield Cup.

The race has to have a minimum topweight of 58kg so if Green Moon doesn't run weights will be raised at least 1kg with Sea Moon and Red Cadeaux next in the handicaps at 57kg.

Multiple Group One winner Manighar has 56.5kg, Melbourne Cup runner-up Fiorente has 55.5kg along with veteran Metal Bender, while international galloper Dandino has 55kg.

Dandino is on the third line of betting at $15 along with Fiorente while Jet Away, who has 53.5kg, holds the second line at $11.

ATC Australian Oaks winner Royal Descent is the highest-weighted four-year-old mare with 52.5kg while her Chris Waller-trained Queensland Derby-winning stablemate Hawkspur is the second-highest weighted four-year-old behind Super Cool with 53kg.

The Caulfield Cup, which has a capacity field of 18, is on October 19.