Powerhead compatibility??

I purchased a 84 yamaha 90 hp with a bad powerhead with the intent of putting the good powerhead from my 98 90 hp on it. I am switching the powerhead (hopefully) to the older motor because the 98 was in saltwater and the steering tube has become one with the brackets and is rusting from the inside.

Before I get too far into this, I want to make sure this is as simple as I expect. I have searched the forums without any luck. I have compared the part #'s (which do not always match up) but since the motor has not changed that much, I am wondering what I may expect from such an undertaking.

Would anyone who has experience with the yamahas please respond to this post

[boats.net]

Never tried that, there have been a lot of changes and not sure what you will run into.

[jb123]

if the base gaskets match shouldnt be a problem, just check where you buy them.