Don't know if it's the same, there is no reference to South Africa but they look quite similar:
In a popular website I found that the K4 Special had an Austin K4 6 cylinder engine and was raced in Tasmania c1966. In about 1965 the car was first purchased by Bernard Harbeck.
It could be based on an earlier K4 Special, run by Burnie driver Stan Allen, whose single seater open wheel racing car was based on a lengthened Ford 10 chassis and K4 engine, from 1958-1961, after its earlier career as Allen's Fiat Special, running a supercharged 1300 Fiat engine in the same Ford 10 chassis.