Of the Nevergos still in circulation this would be the oldest in Oz -
VH CYV
Model: PA-31
Serial number: 31-18
Aircraft first registered in Australia: 06 July 1987
Year of manufacture: 1967
Got at least one flight with that one in the logbook.
While this one has been here the longest -
VH PDN
Model: PA-31
Serial number: 31-177
Aircraft first registered in Australia: 13 May 1968
Year of manufacture: 1968
And I did my PA31 endo in this one -
VH WNC
Model: PA-31
Serial number: 31-420
Aircraft first registered in Australia: 08 September 1998
Year of manufacture: 1969
When it was still VH-ZJZ