It is sold by Roy Gripski and Sons, in the GA Power Equipment Spares Catalogue. The adapter is for the Old Style Victa Engine, not the new one piece crankcase. It adapts the Tapered Crankshaft to a 3/4" Clutch, retails for $46. Most Mower shops in Australia have this catalogue and can order it for you.
Hope this helps someone.
Charley
Hope this helps someone.
Charley