Three prototypes were built by hand in 1946 by American and Australian engineers at the General Motors workshop in Detroit.
Months of durability and performance testing were undergone in the US before the three prototypes were shipped to Australia.
Prototype number one was first registered (as a Chevrolet) in Victoria as JP-480 on 12 February 1947.
It survives as part of the National Museum of Australia collection.
Prototypes two and three were registered at the same time as JP-481 and JP-482.

A further two prototypes were built in Australia; the first was registered as KJ-400.
Owned by Australian businessman Peter Briggs between 1980 and 2013, the car's value was estimated to be worth over A$1 million when it was put up for auction in the Motorclassica auction Melbourne, in October 2013.
The second Australian-built prototype was registered as KY-442.
All five prototypes were registered as Chevrolets.

Only two were used for photographic purposes.
They were:
Prototype No.1, JP-480, dark colour—Seine Blue (not Cadillac Blue)
Prototype No.4, KY-442, light colour—Gawler Cream.

In the absence of an established supplier base in Australia for auto-making, new forging facilities had to be set up for producing crankshafts and a new foundry was set up for major castings.
In order to hasten the project to production some simplifications were incorporated.
There were no direction indicators, there was no provision for heating or demisting, and at the rear there was only a single, centrally positioned, tail lamp.
Because of the mild climate in most of the populated areas of the country, it was found possible to save weight and cost by using a relatively small 6-volt 11-plate battery.
Interior trim was minimised: weight reduction was pursued "with great vigour" and, in view of the 2,247 lb (1,019 kg) weight in "running trim", a success.
Three prototypes were built by hand in 1946 by American and Australian engineers at the General Motors workshop in Detroit. Months of durability and performance testing were undergone in the US before the three prototypes were shipped to Australia. Prototype number one was first registered (as a Chevrolet) in Victoria as JP-480 on 12 February 1947. It survives as part of the National Museum of Australia collection. Prototypes two and three were registered at the same time as JP-481 and JP-482.
A further two prototypes were built in Australia; the first was registered as KJ-400. Owned by Australian businessman Peter Briggs between 1980 and 2013, the car's value was estimated to be worth over A$1 million when it was put up for auction in the Motorclassica auction Melbourne, in October 2013. The second Australian-built prototype was registered as KY-442. All five prototypes were registered as Chevrolets. 
Only two were used for photographic purposes. They were:
Prototype No.1, JP-480, dark colour—Seine Blue (not Cadillac Blue)
Prototype No.4, KY-442, light colour—Gawler Cream.
In the absence of an established supplier base in Australia for auto-making, new forging facilities had to be set up for producing crankshafts and a new foundry was set up for major castings. In order to hasten the project to production some simplifications were incorporated. There were no direction indicators, there was no provision for heating or demisting, and at the rear there was only a single, centrally positioned, tail lamp. Because of the mild climate in most of the populated areas of the country, it was found possible to save weight and cost by using a relatively small 6-volt 11-plate battery. Interior trim was minimised: weight reduction was pursued "with great vigour" and, in view of the 2,247 lb (1,019 kg) weight in "running trim", a success.
Holden 48-215