Merc 800 - Which lower unit to keep ???

[Moody Blue]

Currently have 3 lower units off early 70's 80hp Mercs. Is there any way of "testing" them to see which of the three are in the best condition, other than hooking them up to the motor and running them? Even that is a very subjective test. Thinking about the seals, bearings, gears etc etc. Any lower unit experts out there?

Want to put the best on the motor and keep the next best as a spare and sell the third as a parts or rebuild unit.

 

[Moody Blue]

Re: Merc 800 - Which lower unit to keep ???

No one has any suggestions or advice? Must be something I can do to check condition of these things.