Hi Dave, and
on another great score mate!
Having a Kirby installed raised my curiosity as well.... and I have found that the 1973-74 range of Imperials (ie. 14" - 24") all had the Series 70 Victa engines fitted. In fact there were 2 models of the 24" machine....the 'standard' and the 'heavy duty'.
This leads me to believe that your machine is much later...maybe there is a date on the Instruction Manual? This would be good for the archives Dave.
