In 2002 Holden Motorsport was looking at running a Holden Monaro in the first ever Bathurst 24 Hour endurance sports car race against the likes of the Lamborghini Diablo GTR, Ferrari 360 N-GT, Chrysler Viper ACR and Porsche 911 GT3 that were regulars in the Nations Cup Championship. After the Holden Racing Team reportedly turned down the job of building the Monaro, Garry Rogers Motorsport accepted the job of building the car as well as running it. The Monaro was originally intended to be debuted in 2003, but after the go ahead had been given for the Bathurst 24 Hour to be run in November 2002, the car's build and development time shortened to just 9 months.

The Monaro's ran a GRM developed version of the Chevrolet Corvette C5-R's 7.0 litre (427 cui) motor which had taken numerous class wins in the 24 Hours of Le Mans and the American Le Mans Series. The GRM engines were built by the team's engine builder Mike Excel who designed a special inlet manifold for the engine. The aero kit (front and rear wings) on the Monaro was based on the similar aero package used on the Holden VX Commodore that ran in V8 Supercars (the Monaro road car was a 2-door coupé version of the VX Commodore), though the rear wing was larger than a V8 Supercar's and to conform to GT regulations had to be lower in height than the cars roof line. GRM and Holden Motorsport also used a lot of their V8 Supercar components on the Monaro to make it a stronger race car. The car ran on 18 x 11 inch wheels at the front and 18 x 13 inch wheels at the rear while the wheels were supplied by OZ Wheels. The cars were also fitted with a 6-speed sequential gearbox made by Melbourne-based racing gearbox supplier Peter Holinger.

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