Hello<br />I have a 4.3L Merc Sterndrive with a 18 foot Campion Open Bow boat. Approx weight is 2400 lbs.<br />RPM with existing 14.25" x 21P BlackMAx prop is at the upper limit with normal load and trim up (4700RPM). If I remember correctly speed is around 43-46MPH using GPS.<br />As I want to...