Originally Posted by: Warren Turnbull 
The HB becoming a Holden I believe is to do with the re organising of the dealer network. In the mid 60s you had Holden Dealers that sold the car known as Holden (Standard, Special and premier) then you had Chevrolet, Pontiac, Bedford and Vauxhall dealers. Some dealers were multiple, so you would see signs like Holden and Chevrolet dealer.
The Vauxhall dealers were about to be shut, but the Viva was still selling well in its market, and GMH would have already had plans for a local update in 2 years time.
So the Viva was dropped and replaced with a "Holden" Torana, sold through Holden dealers. Had there been no plan for the LC Torana the Viva would have vanished like the Cresta.
Two years later Chevrolet and Pontiac dealers ceased with the release of the Brougham.
If the dealer network did not change in the 60s the Gemini would have probably been sold through Isuzu dealers which would have then taken on Camira. It may have also made it difficult for the transition from Holden to Commodore.
Rationalization of marques began in Sept 1948 due to:-
G.M-H Dealership ANNOUNCEMENT (South Coast Times and Wollongong Argus Thu 9 Sep 1948 )
Now that production of the new Australian car has commenced, and importations are being greatly expanded of British Vauxhall cars and British Bedford trucks, General Motors-Holden's Ltd. have pleasure in announcing the following distribution arrangements :
As Authorised G.M-H Dealers for VAUXHALL and BUICK Cars, BEDFORD Trucks and Utilities
BOYDED PTY. LTD.,61 Keira Street, Wollongong. Phones 802, 242.
As Authorised G.M-H Dealers for HOLDEN — General Motors NEW AUSTRALIAN Car CHEVROLET and OLDSMOBILE Cars, CHEVROLET Trucks and Utilities, MAPLE LEAF Trucks
DWYER'S GARAGE, 37 Lower Crown Street, Wollongong. Phones 97, 469.
With car and truck importations from North America limited to a fraction of their former volume by dollar restrictions, the Australian public's needs of motor
vehicles must for time being be drawn chiefly from two sources — Australian and British.
To meet this situation, General Motors--Holden's Ltd. have taken two major steps:
(1) they have designed their new Australian car and have built new modem plants for its production in Australia at a cost running into several millions of pounds.
(2) they are wholeheartedly supporting the British drive for exports by vigorously marketing British Vauxhall cars and Bedford trucks, which are already Australian sales leaders.
General Motors-Holden's Ltd. wish to record their pleasure at the above Dealership arrangements, which will assure the public of the high standard of sales and
Service Aids that an essential to G.M-H. policy. GENERAL. MOTORS - HOLDEN' S LTD.
This rationalization continued until 1955 with hundreds of dealers effected. As Holden progressed in the market, dealers were later issued Holden franchises when Vauxhall and Chevrolet faded (as you have mentioned.) The distribution of marques was not always consistent as a group and varied in different locations and dealerships. The globalisation of GM (in Australia) began with the 48-215. The re-distribution of marques in the GM stable was a post war adjustment to supply and demand, market share and positioning all in the direction of globalization. GMH's descriptive rationale for these changes was not always consistent.
