Johnson powerhead swap attempt

[oceanhorse]

hello crew
What I'm trying to do is swap the powerhead from a 1992 15 horsepower Johnson on to a 1985 Johnson 9.9 leg,
Are the shaft splines compatible between these two years/modles?
Any advice appreciated, i tried to interpret the chapters on compatibility but to no avail. What set of gaskets might i require? I haven't done this before, not new to wrenching.

 

[racerone]

same spline arrangement.

 

[oceanhorse]

Thanks raceron, ill tackle it