Listed here is a USED Mercruiser Alpha 1 Gen 1 Gearcase Assembly.  Both offered are Genuine OEM Mercruiser drives NOT cheap Chinese aftermarket replacements.  Both drives have wear from years of use but are completely operable.   PROPELLLER IN PICTURES DOES NOT COME WITH GEAR CASE.  Please come by and take a look if interested. These both were used on a Sea Ray with the 5.7 350 V8 so I believe they are the 1:50 gear ratio but don't know for sure without disassembling them.  May work with many 5.0 with some reproping.  These style gear cases were used throughout the 1980s and early 1990s.  Like stated before two are available.  I am upgrading to newer units so I don't need these anymore.  One is loose and one is mounted to the boat currently so I can actually demonstrate one works.  I have used both of them.  One was the original with the boat and the other was a spare.  I cant remember which was which but both were used in freshwater only as far as I know.  The boat spent its entire life on a freshwater Orlando chain of lakes and never left so it never saw salt.  Please come by to take a look if interested.  These are old units and I would like you to inspect them before purchasing.  I have them listed at the shop as well as other platforms.  Please feel free to contact me before purchasing if you have questions or need help with compatibility.  Thank you for your interest.  Steve MMSLLC :)