I have a 1991 Mecury Alpha one Gen I sterndrive with a 1.98-1 gear ratio. It
is mounted to a 3L 4 cyc engine but the sterndrive ceased this summer and I
have found another one but it has a 1.47 ratio. Can this sterndrive be
mounted onto the same engine. What about a later year model like a 1995
alpha one gen one would that fit? Lastly what does the upper unit gear ratio
relate to? Torque...engine speed?

Lots of questions