Mercruiser 165 replacement options?

[johnsland8]

I apologize if this has been asked before, and I'm sure it has, but I cannot seem to use the search page with any success. Anyway...

I have a Mercruiser 165 (inline 6) in my 1989 Bluewater.
Is there any way I can find out what other engines, if any, would be a bolt on replacement/alternative?

Thank you in advance for any help you can provide...