[citation needed] During the winter of 1974, the management of the speedway announced that the track surface was being changed from clay and dolomite to asphalt.Also announced at the time were extensive renovations including a fully enclosed grandstand with a glass-enclosed restaurant, a VIP lounge and a 3-storey control tower, all aimed at increasing the track's spectator capacity to around 35,000.Liverpool Speedway's biggest annual event was the Marlboro Grand National 100 Lap race which was first run in 1971 and won by local driver Rick Hunter.[citation needed] Grand National Sedans were a new breed of cars developed especially for Liverpool Raceway, though some were easily adapted for the many dirt track speedways around Australia.American drivers such as Gene Welch, "Big Ed" Wilbur and Rodney Combs became regulars in Australia and the action on the track was often described as "World Championship Wrestling on Wheels".The test matches took place both on the dirt track and the pavement with the usually good natured crowd totally against the visiting Americans.Foyt was again the winner this time passing local hero and National Champion George Tatnell in the dying laps.[citation needed] Liverpool, which was renamed in 1980 to become the "Liverpool City Raceway", continued to run the Australian Speedcar Grand Prix on both the asphalt and dirt until 1988 with such winners as 10 time Australian Sprintcar Champion Garry Rush in 1977, Ron "Sleepy" Tripp of the United States in 1983 and 1984, and after the track had reverted to a clay surface, World of Outlaws legend Steve Kinser would swap his Sprintcar for a Speedcar and win in 1986.Also, World Champions such as Ivan Mauger (New Zealand), Ole Olsen and Hans Nielsen (Denmark) and Americans Bruce Penhall, Bobby Schwartz, Dennis Sigalos and Shawn Moran regularly raced at Liverpool when competing in Australia.In a major win for the Liverpool City Raceway management and promoters, the track was awarded the 1982 Speedway World Pairs Championship Final.By 1989 the speedway was under threat by the so-called urban sprawl, and this led to the reluctant closure of the venue to make way for new housing and a shopping complex now known as the Valley Plaza and for Winnall Reserve, Rugby League Fields,the home of Hinchinbrook Hornets.