When it was released in 1969, the six-cylinder LC Torana was hailed as a new-sized car for Australia.
Compact yet powerful, it filled the gap between small four cylinder cars and the increasingly larger six- and V8-powered family sedans and wagons.
And yet, in 1965, when Holden’s product planners were considering what was needed in the 1970s, they were thinking only of a four-cylinder car to bridge this gap.
The planners knew that the current Vauxhall Viva and its 1967 replacement, which would be called the HB Torana, had a weakness.
And that was the size of its engine.
At 1.2 litres the four was okay in the UK.
In Australia, however, where a six was considered the minimum acceptable form of propulsion beyond the suburbs, it was not a selling point.
The Torana of the 1970s, which was being called the “HC”, would need an engine of between 1.5 and 2.0 litres to be competitive in the long run.
Adding to the problem was the federal government’s edict requiring locally built cars to achieve at least 95 per cent local content by January, 1970.
That meant any engine would need to be built in Australia to meet the rules.
But what engine?
Holden did have some options.
There was Vauxhall’s yet to be proven 97.4 cu.in/1.6-litre slant four, due for release in 1967.
It had the capacity to be stretched to 139 cu.in/2.3 litres.
Another proposal was cutting two cylinders off the existing Holden “red” six.
This would deliver a range of four-cylinder engines spanning 83 cu.in/1.36 litres to 124 cu.in/2 litres.
While the engine issues were being evaluated, the design of the HC was being considered.
There were two styling paths.
One was a mild restyle of the yet to be released HB Torana.
Another was new sheet metal designed in Australia.
Meanwhile, Holden realised that tooling up to build the 1.6-litre Vauxhall engine locally was too costly.
Next, cutting two cylinders off the red six was not as cost effective nor a mechanically viable solution as first thought.
What to do?
In a typical demonstration of ingenuity that so often characterised the Australian automotive industry, the problem was re-framed.
Why spend time and money developing a big four?
Why not reduce the existing six’s capacity to around two litres?
And so, the 138 cu.in/2.25 litre engine was created.
It ticked all the boxes for power, local content and cost.
It meant the Torana could be offered as a four and six.
It opened up a new category — a reasonably powerful six in a small light-weight car.
And, tantalisingly, there was potential for a high-performance Torana using the larger capacity versions of the six.
The new engine also influenced the styling options.
And the rest is history.
David Burrell is the editor of retroautos
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