Holden boasts a rich heritage of special-build high performance road cars that became winning race cars stretching right back to Stormin’ Norm Beechey’s EH S4, which makes the X2 version of the HD and HR models of the mid-1960s an awkward fit in such a stellar line-up.
As a competition car, the stock HD Holden faced an uphill battle from the start given that it shared the skinny track dimensions of the EH and a wheelbase almost as short yet was burdened by a bloated new body style that was heavier and larger than its predecessor in every dimension.
In addition to its extra weight, the major handicap was a higher centre of gravity, which exaggerated the powerful effects of weight transfer resulting in poor handling. The engine was also mounted further forward in the chassis, putting more weight over the skinny drum-braked front wheels.
Not surprisingly, the availability of a higher performance twin-carburettor ‘X2’ engine option tied to a three-speed column manual for this lot left Holden racers scratching their heads. Although HD X2s saw competition use in the mid-1960s, including the annual Bathurst 500, they could not emulate the success of the S4.
The marginally improved handling of the HR facelift that followed failed to fire new race track interest in the X2 option, even though it was based on the larger 186 cid (3.0 litre) engine with a slight increase in power.