The Holden Torana GTR-X Concept was designed during the era of the LC series Torana, and was seriously considered for production in the early 1970s. The GTR-X had a wedge-shaped fibreglass body featuring a hatchback rear access, and the prototype cars had LC Torana GTR XU-1 mechanical components.
The Holden Torana GTR-X Concept looks similar to iconic sports cars of the 1970s, such as the Ferrari 308 GT4, Lotus Esprit and the Mazda RX-7. It weighed in at 1,043 kg / 2,299 lb) and has a top speed of 210 km/h (130 mph). The Torana GTR-X in production would have been the first Holden car to be factory fitted with four wheel disc brakes.
When Holden released a promotional brochure about the GTR-X, they said - "Its long, sleek hood is accentuated by a low wedge-shaped grille. The body line sweeps up at the rear to an elevated tail light assembly. Simplicity is the keynote. It is achieved by concealed headlights, sharp windshield rake, recessed parking and turning lights, and flush petrol filler access and door handles. Front and rear bumpers assume the contour of the body. To identify the car, the GTR-X identification is contained within a crisp black and orange stripe running parallel to the rocker panel".
The Torana GTR-X was highly developed by Holden from concept, and even though brochures, photography and promotional films were produced to show how serious they were in putting the car into production, the company was ultimately unable to justify the high cost of committing itself to production given the size of the Australian population in those days.
Source: Wikipedia (original)