Offshoreonly.com - Bravo 3 to a Bravo 1 XR

Little impute needed;

I have a 93 Formula 252 BR that I plan on making some drive changes to. I am dropping in a 580 hp BB this winter and I am going from a Bravo 3 (1.5 ratio) to a Bravo 1 XR (1.5 ratio). The question I have is; in its present state, when I run flat out with the Bravo 3, with 26p SS props; I am running 4650 rpm’s and 53mph (GPS), on flat freshwater. Changing only the Bravo 3 to a Bravo 1, using a 26p SS prop, will my rpm be greater than, less than or the same as the Bravo 3. My thoughts are that I would actually pull some more rpm’s simply because I will be displacing less water (i.e.: 1 prop working instead of 2) and the engine will gain more power. My buddy thinks it will be the same. Any thoughts or experience? Thanks, pax2you