Re: omc cobra interchange?
Nope, wrong gear ratio.
Before you ask, no, just changing the prop won't make it any better.
Well, the upper and lower units will bolt right up to one another and will function as an out drive. But you may have a problem with the drive being geared too high/low for your application.
Also, the annode mounted on the front of lower unit may have to be swapped out with the one from the original lower unit. The upper housing is is slightly different, swapping the annode is the only modification.
I have a 19 foot wellcraft that had a bad upper. I used the upper from a 5.7 I had in the shed. Got a free running boat for a couple of gaskets and an hours work.