Now both retired, they were two of Australia’s most successful international drivers of the 1970s, and will bring extra excitement to the Leyburn celebrations.

Brown started as a 19-year-old in 1969 and retired 11 years later to focus on a business career. In that period, he won the Australian Grand Prix (1977), New Zealand Grand Prix (1975) and Rothmans International Series/Australian National Formula 1 (1977, 1978).

He was the only Australian to win the Tasman Series when he won the prestigious summer competition in 1975. The series which began in 1964, attracted many European-based Formula 1 drivers.

Brown also raced in the United States against many of the world’s best, including Mario Andretti, James Hunt, Al Unser, Sam Posey and Vern Schuppan, mostly in Lola F5000s. In 1976 he drove a Wolf-Williams at the USGP in his sole Formula 1 appearance for 14th. In 1978, he finished second in the American Can-Am series in a Lola sports car.

Allison started racing in a Ford Escort at Lakeside in 1970, then almost never drove a tin top since. He also raced Lola F5000s in Australia, the US and New Zealand. He took pole position for the 1975 Australian Grand Prix and twice competed in the race since.

After a year in the American F5000 series, Allison went to the United Kingdom where he competed aboard a Chevron B37 F5000 in the 14-round Shellsport International series for Formula 1, F5000, Formula 2 and Formula Atlantic cars.

He finished seventh overall with four podiums and three poles. He was presented with the coveted Grovewood Award as the most promising Commonwealth driver, by Stirling Moss.

In the 1977 Aurora AFX British F1 Championship he won at Mallory Park in a March-Cosworth. After he declined a F1 opportunity, and a two-year hiatus, he won the 1981 Formula Pacific Series in Australia and the Shah Alam Grand Prix in Malaysia.

“The present-day Australian Grand Prix in Melbourne can trace its lineage back to Leyburn. No other pre-Formula 1 Australian Grand Prix is celebrated like Leyburn’s, and we’re thrilled Warwick Brown and Bruce Allison will be with us this year,” said Sprints President Tricia Chant.

The 75th commemoration of the Australian Grand Prix will be the highlight of the annual Sprints, which were founded in 1996 to keep alive the unique grand prix heritage of the tiny Darling Downs town.

Organisers have accepted a record 243 entries of historic, classic and performance cars across 64 classes for the round-the-houses time trials. Off-track activities include a vintage caravan display, Show ‘n’ Shine competition, racing car displays, charity auction, fun run and live music.

The competition starts at 8;00am on Saturday and Sunday. Adult tickets are available on-line or at the gate for $25 a day or $35 for the weekend, with children under 14 free. On-street parking is free. The event also is holding a raffle to win a Bathurst 1000 weekend for two valued at more than $11,000 or five $500 Supercheap Auto vouchers. Tickets can be bought on the website.