THE excitement surrounding this weekend's 20th Historic Leyburn Sprint continues to build as the town braces for an inundation of rev-heads from near and far.

The weekend program has received another boost with a rare race car built and raced by Sir Jack Brabham confirmed as a last-minute attraction.

It will celebrate the life of the late triple Formula 1 World Champion.

The 1967 BT23C-1 single-seater will appear in demonstration runs across the two-day time trials event, staged on the closed streets of the tiny Darling Downs village.

A near-record total of 230 historic, classic and performance cars spanning 90 years has been entered for the Sprints, which celebrate the running of the 1949 Australian Grand Prix on an ex-wartime airfield outside the town.

The Brabham demonstration runs will be a tribute to Sir Jack, who competed and won at the airfield track in 1953, before he moved to England to become a famous driver and the world's largest racing car builder.

He had already won the third of his championships when he and partner Ron Tauranac built the 1.6-litre, Ford Cosworth-powered BT23C-1 for the Formula 2 category.

It also was driven by another well-known Australian, Frank Gardner, before being sold to team owner Frank Williams for Piers Courage to drive.

Sprints Race Director Mike Collins said he was delighted the event had secured the appearance of such a significant car as the Brabham, which has resided recently at the National Motor Racing Museum at Bathurst.

"This is a great piece of Australian racing history and we're grateful to the car's custodians for bringing it to Leyburn," Collins said.

"The Brabham is just part of an extraordinary line-up at Leyburn this weekend. We'll also see demonstration runs by the famous Mildren-Waggott 'Yellow Submarine' racer and 78-year-old Bo Seton in his ex-Bathurst Ford Capri, plus a diverse range of competing cars from a 1925 Austin Brooklands to an Indianapolis roadster.

"It's fitting that our 20th anniversary Sprints are shaping as one of the best events yet. We're expecting more than 350 cars on and off-track, great racing from some truly top drivers and great weather, it's a weekend not to miss."

Competition starts at 8am on Saturday and Sunday.

Adult entry costs $20 per day or $30 for the weekend, with accompanied children under 14 years admitted free.