Re: more power?
It depends on how far you want to go and how much work you are willing to do. Scroll down and see my replies to "More Speed" and "Before and After Force restoration".
It also depends on the year of your Chrysler. If it is earlier than 1979, with the two piece lower unit and 18 splined prop shaft, then you almost certainly have a 1.78 to 1 lower unit gear ratio. Switching to a 2 to 1 gear ratio from a 90 hp and going up 2 inches in pitch will yeild 4-5 MPH more. Props, however, are difficult to find and you would best put an ad in The Chrysler Crew.
If it is later than 1979, you need to check if the gear ratio is already 2 to 1.