[C320-list] Gearbox Reduction

[Colin Evans]

We have a 2000 model Catalina 320 with a Yanmar 3GM30F engine and a Kanzaki
gearbox. 
I wish to change the propeller and the suppliers require the reduction
ratio.
The plate on the gearbox has model KM2P and  Yanmar  indicates that there
should be another letter either S or G following, which will nominaate the
reduction of 2.21 or 2.62.
Also on the plate are the words "Gearbox Ratio", but no information
following.
How can I determine the reduction ratio.  Were they all 2.62 ?
*************************
Regards
Colin Evans
Watermark 
2000 C320 # 774 
Lake Macquarie, Australia