Re: Matching lower units
For the most part, gearcases interchange for 650, 75, 800, 850, 90, 1000, 1150, 1250, 1350, 140 and 150, all the way from the 1960s into the 1980s. They vary somewhat in internal design and gear ratios, but they'll all fit. Different gear ratios can be compensated with different pitched props. (I'm talking about the inline 4s and 6s of that era.) Naturally there'll be a difference between long and short shaft gearcases.
