Bravo 1 Prop Change

[FuelishBehavior]

Going from a 300 HP 454 engine to a 500-550 hp 496 engine. Currently have a sstl 21P x 14.8" prop. Any ideas on how much I will need to prop up or where to start? Engine max RPM to be around 5600 RPMs. Boat is a '93 Crownline 225 CCR and weighs about 3800 to 4000 lbs. (guessing). Outdrive is a Bravo 1.

 

[alldodge]

My 23 foot rinker with the same setup (1.50 ratio) will do 60 mph (4800 rpm) using a 21. Being able to go to 5600 rpm even with 8% slip your bumping the 70 mph mark. I would start with what you have and the hole shot will be quick. My guess is the most you will need is a 23 pitch and push you into the 75 range.

Then once you get all that done you need to spend some money on hydraulic steering

 

[FuelishBehavior]

I'm more of a cruise speed type of person and don't do much hole shot stuff. Outdrives get pricey. I'm looking for the fastest cruise speed at the lowest RPM with the highest possible top speed at 5600 RPM's. I was thinking the 23 myself. Not sure my boat would handle that kind of speed either. Can you elaborate on the hydraulic steering though? I already have "power" steering which is hydraulic.

 

[alldodge]

The PS we has some slop in it, just the nature of the beast. When a boat starts getting above 60 mph, and real bad above 70 mph that bit of slop can cause the boat to go wild. The full hydraulic steering is things like Latham and other performance steering makers. The pump is removed and now you have a rock solid connection between the helm and the drive. The helm wheel is the pump and the drive is moved by hydraulic cylinders most often mounted outside on the transom

http://www.lathammarine.com/steering.htm

 

[FuelishBehavior]

Thanks for the info AllDodge. I'll check into it. My PS does have some slop for sure which was concerning me.

 

[Bondo]

My PS does have some slop for sure which was concerning me.

Ayuh,..... Common wear points in yer system are the helm, cable, the clevis pin connections at the transom, tiller arm, 'n gimbel ring,....

There's the tiny bit of slop in the valve actions of the P/S unit, but amounts to really nothin' anyways when runnin',.....

I moved this question to the Prop Forum for ya, seems a better fit,...