Hello, folks!
As all 1st time boat owners I have a lot of questions and only people who can answer are sales personal who advise with parts they sell.
I can fix most mechanical-electrical problems on non-professional level, which means that many things I can not fix 
Anyway, the question I stuck with for now is: The motor on my 1988 Bayliner is 2.3 Cobra 4 cyl with original Cobra out drive. The friend of mine presented to me the out drive from his ex boat. It is also Cobra, but from 5.0. Upper unit looks absolutely the same (in and out) but Lower unit has different Gear set.
The question is: May I use this out drive from 5.0 on my 2.3? And if yes, what differences should I expect?
Thank you all and I will really value all the info!