new member needs some help

I bought a used 25 hp evinrude long shaft that has no sr# or model # plates, Its dark blue with the shifter on the tiller housing. question #1: how can I find out what year it is? #2: I want to change it to a short shaft, I have disconnected the shift rod down behind the water screens, removed the impeller cover and slid the lower unit out including the 5 " spacer, How do you get the shift rod disconnected up inside the housing????? I can see it connected to the exterior shift unit with a cotter pin but its not acessable , do I have to remove the housing from the power head? any help would be greatly appricated!

Remove the powerhead in order to change the upper shift rod.

thanks for that info.