Drive ratio

[classic16]

I would like to know which drive ratio I need to purchase for my boat.
It is a Donzi classic 16, with a 350ci, it is around 250-280hp. I am also using a Mirage 23 pitch prop. The last outdrive was a 1.62 ratio and I was hitting the rev. limiter @ 5100rpm. I would like to keep the same prop.
Thanks.

[Tech Support]

If you are not operating over 6,000' above sea level then the 5.7 motor would run a 1.47 to 1 ratio on boats under 19' long. You will have to check your WOT rpm with your prop to see if it is OK.

Tech Support