The race was held for cars complying with the Australian version of International
Group A touring car regulations with three engine capacity classes.
Class A – Up to 2000 cc Six cars were entered for Class A, including four
Toyotas, two of them factory supported, an
Alfa Romeo Alfetta which did not start and a
Volvo 360 which also failed to start.
Class B – 2001–3000 cc With a multiplication factor of 1.4 applied to cars with
turbocharged engines, a 2000cc car with a turbocharger was rated at 2800cc for the purposes of the class structure. This saw the factory supported turbocharged
Mitsubishi Starions and a
Volvo 240 compete against non-turbo
Audi 5+5,
Toyota Celica Supra and the factory-backed
Alfa Romeo GTV6. It was the first time since the
1973 race that there was no
Ford Capri on the grid. Also, after having 13 on the grid in
1984, there was only one solitary
Mazda RX-7 at Bathurst in 1985, running the
12A rotary engine without peripheral porting.
Class C – over 3000 cc The class featured
Holden VK Commodore SS V8s, the big
5.3L V12 Jaguar XJ-S', the
4.9L V8 Ford Mustang GT's, the
3.5L V8 Rover Vitesses and the
3.5L Straight-six BMW 635 CSi. Although the HDT Special Vehicles road car division had failed to build the required 500 "evo" model Commodore's by the 1 August
FISA homologation date, there were enough 4.9L base model Commodore road cars to allow Holden runners to use the smaller capacity 4.9L V8 engine in order to come under the 5000 cc class cutoff and be able to run lighter. However, the engine was still the production V8 which came with known issues such as a single row timing chain (double row was preferred) as well as somewhat brittle valves and rockers, issues that would be fixed with the full blown Group A SS version that would appear in 1986. Use of the smaller Holden V8 also allowed the use of a 5-speed racing
gearbox rather than the VK's production 4-speed. For 1985, all Commodore's regardless of engine size ran the standard VK Commodore body devoid of the front and rear spoilers that would appear on the 1986 cars Thus the Holden Commodore V8's ran in two different configurations: • 4.9L (4980 cc) - 5-speed gearbox (
Getrag 265) and a minimum weight of • 5.0L (5044 cc) -
Holden production 4-speed M21 gearbox (known colloquially as the
"Aussie 4 speed") and a minimum weight of Due to high demand after Australia had gone wholesale Group A in 1985, there ended up being a lack of available Getrag gearboxes by the time of the James Hardie, thus some of the 4.9L Commodores were forced to use Holden's production 4-speed box. Unfortunately for the
West German based transmission company in 1985, being the major supplier of Group A racing gearboxes for both touring cars and rallying saw them struggle to keep up with demand with the increasing amount of Group A racing across the globe. ==Hardies Heroes==