The 1984 Castrol 500 was an endurance motor race staged at the Sandown Park circuit in Victoria, Australia on 9 September 1984. The event was open to Group C Touring Cars, competing in two engine capacity classes, Up to 3000cc and Over 3000cc. It also included a class for Group A cars which were to replace Group C cars in Australian Touring Car racing in 1985. The race, which was held over a distance of 503 km, was Round 3 of the 1984 Australian Endurance Championship.

The Holden Commodore (VK) is a mid-size car that was produced by Holden from 1984 to 1986. It was the fourth iteration of the first generation of the Holden Commodore and introduced the luxury variant, Holden Calais (VK) sedan.