Reply To: Mid 1950’s 10 to 18 horse lower units

[frankr]

That is a tough question to answer.  Read fleetwin’s reply, above.  The basic gearcases for the 22 cubic inch motors were used for over 20 years, and for the most part, they are interchangeable.  But the surprises come when you go to buy internal parts.  Or even stuff like the shape of the cavitation plate.  Doesn’t make any difference, unless you are going for an authentic restoration for judging.