A great grandson of one of the most famous grey racehorses has produced a barnstorming finish to win the annual VRC Oaks day race named after another high profile grey.

The Mike Moroney-trained Tribal Wisdom, a descendant of 1989 Japan Cup-winning mare Horlicks, arrived just in time to grab Harbour Grey on the line in Thursday's Subzero Handicap (1400m) to win by a half-head.

The annual race during the Melbourne Cup carnival at Flemington is restricted to grey horses and is named for the 1992 Melbourne Cup winner.

Moroney trained Horlicks' most famous son, the 2000 Melbourne Cup winner Brew.

"It's been a great family to us," Moroney said.

Tribal Wisdom won the Listed Gosford Guineas last season and Moroney believes the gelding has plenty of talent.

"We always thought he was Group class and he already won a stakes race early in his career," Moroney said.

"He's still learning what it's all about and is still only lightly raced. He's always had natural talent. I think you'll find he's a pretty smart horse."

Moroney and jockey Patrick Moloney said the intention had been to have Tribal Wisdom closer to the pace but the gelding didn't begin well enough.

Moloney had to angle Tribal Wisdom off heels to get into the clear in the straight and admitted the gelding had to a big task ahead of him to reel in Harbour Grey.

"But he thought he'd do a little bit of showboating in front of his grey mates today," Moloney said.