Bravo 1 / 1993 Crownline / 7.4L / 225 CCR

[FuelishBehavior]

I currently have a 300 hp 7.4L bravo 1 with a 21P prop. My new 496 stroker engine will be right around 400 hp. Is there a calculation that I can use to guess the new prop size. My rpm range is going to go from a maximum of 4600 to approximately 5500 as well. Boat weight is approximately 4000 - 4500 lbs.

 

[tpenfield]

Not really a calculation, more of an approximation, as far as I know. If you are increasing HP by 1/3, then expect your speed to be increased by about 10%. Therefore, outdrive ratio being the same you could go up about 10% in prop pitch to achieve similar top RPM of the engine.

So, you could try the 21 pitch, since the new engine can rev higher, but be ready to go with a 23 pitch.

 

[Bondo]

My rpm range is going to go from a maximum of 4600 to approximately 5500 as well.

Ayuh,.... Leave the same prop on it, 'n see what it does,.....