Affectionately known as “KJ 400” (after the number plate), the hand-shaped prototype will be auctioned at the upcoming Motorclassica event by the Theodore Bruce auction group.
While myths and stories of the earliest Holdens abound, it is believed that KJ 400 may be the fourth of five 48-215 prototypes - and the first to be built entirely in Australia.
The first three prototypes were fully or partly made in the US and shipped to Australia for testing.
It is believed that only one of these three vehicles has survived, known as “Holden Prototype Car No. 1”, which was restored and is now on display at the National Museum Australia.
Therefore, KJ 400 could be the oldest Australian-made Holden and the second oldest in existence.
As Holden was not a recognised carmaker with the road authorities of the time, KJ 400 - like the prototypes before it - was originally registered as a Chevrolet.
The true value of KJ 400 is not known and is certainly open to interpretation, but the rare car was offered for sale as recently as 2011, with an estimated value at the time from its owner of around $2 million.
Motorclassica will be held at the Royal Exhibition Building in Melbourne from October 25-27, with the action taking place on Saturday, October 26.