This what was written about the two cars in Autonews.
Spencer Black had entered both the Monaro and the Camaro. Originally Spencer was to drive the Chevvy with Rod Coppins having a drive in the Holden. In fact this is the way that they practised the cars - at first. However during the second session Coppins took over the Chev while Black took out the Holden. Accelerating out of Harmans Corner the motor went bang, the rear wheels locked up solid and the Monaro-well-she was all over. Bad news inside the sump. So Rod was given the Chev Camaro for race day while the Monaro was taken home.