Hi Grant, and thanks for that info, it really throws the spanner in...and tells us that we know precious little about the rotary time-line...your post suggests that Jeffery's Model 49 could have been made in 1971...not as 1978 as he presumed.
I am trying to find my info that stated that the model 48 was still being produced with the Kirby 2 stroke KAV 74 in 1974/5.

Also I notice that you state that the Model 47 appears on the price list 1-8 -64, which is 3 years before the Model 45 cylinder mower, which was first introduced in 1967. Obviously their numbering system was all over the place! lol
The plot thickens.....but in all sincerity, I believe the Jeffery's Model 48 has the correct engine fitted.
cheers2

Please do not PM me asking for support. Please post your questions in the appropriate forums, as the replies it may receive may help all members, not just the individual member.
Kindest Regards, Darryl grin