Red Tracer will have to carry 59kg in her attempt to go one better than a year ago in the Coolmore Classic.
The Chris Waller-trained mare is topweight for Saturday's Group One race for fillies and mares at Rosehill ahead of stablemates Catkins and Royal Descent, both on 56.5kg.
Emancipation in 1984 and Sunline in 2000 and 2002 both carried 60kg with the next highest-weighted winner Bounding Away in 1987 with 57.5kg.
A close second to Appearance in 2013, Red Tracer ran a slashing third in Saturday's Group One Canterbury Stakes after almost falling at the start.
The Canterbury Classic was won by Appearance who is not in the Coolmore which she won by a nose a year ago.
If Red Tracer does not start, weights will be raised 1.5kg to ensure the required 58kg top weight.
Saturday's Group Three Roy Higgins Tribute winner A Time For Julia has 52.5kg, forcing a change of jockey from Blake Shinn to the lighter Glen Boss.
A Time For Julia used the 1200m race as the lead-up to the Coolmore, beating Lilliburlero by a short neck.
Like A Time For Julia's trainer Peter Moody, Lilliburlero's trainer David Payne believes his mare will be better over the longer distance but she is not a confirmed starter.
"I will talk it over with the owner," Payne said.
"The decision on whether we back her up is up to him. She has come through Saturday in excellent condition so we are looking at it.
"Lilliburlero's best form is over 1400 metres and I think she is looking for even further."
Singapore-based Nathan Berry, who claimed a double at Kranji on Sunday, returns to Sydney for Saturday's meeting and has picked up the ride on White Sage at 52kg.
Visiting Japanese mare Hana's Goal has 54.5 kg with Craig Williams to ride.