Mongolian Khan has firmed in Melbourne Cup betting after being handed a one kilogram penalty.

The Caulfield Cup winner was tightened from $7 to $6 equal second favourite after Racing Victoria's chief handicapper Greg Carpenter announced the penalty on Monday which takes his Melbourne Cup weight to 56kg.

Mongolian Khan will be striving to become the 12th horse to complete the coveted Caulfield-Melbourne Cup double with Ethereal in 2001 the most recent to achieve the feat.

"It was a tremendous win by Mongolian Khan, but a number of other runners produced outstanding performances behind him including Trip to Paris and Japanese stayer Fame Game who ran home strongly into sixth place," Carpenter said.

"The one kilogram penalty takes Mongolian Khan to 56kg - the same weight carried to victory by Gurner's Lane (1982) and Might and Power (1997) when they completed the Cups doubles as four-year-olds.

"It is worth noting that Gurner's Lane won his Caulfield Cup by five lengths, while Might and Power won by seven-and-a-half lengths in track record time."

Mongolian Khan is unbeaten at 2400 metres and steps to 3200m for the first time in the Melbourne Cup on November 3.

His jockey Opie Bosson is confident the stayer will run the distance.

"He just loves staying and look out in the Melbourne Cup," he said.

Baker is also convinced the stayer will handle the Melbourne Cup distance.

Japanese horse Fame Game remains the $4.60 Melbourne Cup favourite.