Firth and John Reaburn finished 3rd in the 1964 Armstrong 500 in a Cortina GT, while Bob Jane won his 4th in a row, teaming with George Reynolds, also in a GT.
The Ford Works Team didn't enter any cars for the 1966 Gallaher 500 at Bathurst and Firth teamed with Ern Abbott in a Morris Cooper S to finish in 6th place.