On the smaller models, I/Os take up a lot of room above deck.
For those who wanted car motor like performance in their boats and were sick and tired of unreliable tempermental chain smoking drink mixers, back in those days, went I/O.
The good thing about I/Os is the new motor cost, what about $4K?
What a deal compared to outboards. But similar manueverability. Of course the outdrive isn't cheap nor that reliable as the motor, just like trannies on inboards.
They get you one way or the other, no avoiding the big hole in the ocean !
The most common model varient of the 20 foot walkaround was the outboard on transom, then outboard on bracket, last I/Os.
Seen very few of the later.
Had an '88 204C myself. So much boat for just 20 foot. Every other manufacturer including BW copied it seeking same success.
Only one original succeeded as long and so great. Seems like millions on the water
It's a Grady.