450 HP with a Bravo 3??

[Stackthepilot]

It started with the best of intentions. Last year I started my engine after winter only to discover improper winterizing had led to a cracked block in my Maxum 2300 SCR powered by a 5.7. I love this boat. I decided to have a local engine builder desing a new engine. It started normally the took on a life of it's own. As it progressed it went from a replacement engine to a ridiculous and high performance project.

Anyway, as the summer went on it was clear we were not going to have this project done anytime soon. With that in mind I bought an Offshore 320 from Boatstoreonline.com. It was a ready to go drop in. I had the marina install it and at the same time had a custom through hull exhaust installed. The drive is an Alpha 1 Gen 2.

Now the other engine is finished. It is a 450 hp with torque to match. I realize that a Maxum Cruiser is not a Scarab. With that in mind, I have spent a fortune on this engine and want it in my boat.

Obviously the Alpah is not going to cut it with this HP. My question is Will a Bravo 3 work? I like the low end control and my kids like to tube. Even with the current setup and tabs it is tough to maintain plane. I have seen boats with 450 HP and Bravo 3's for sale but everything I have read puts the HP max at 400.

I know it seems more like a story than a question but... I Need Help.

[Stackthepilot]

Follow up - I should explain something. The boat will plane and will currently go 45-48 mph. It does not like to maintain plane at 18 to 23 mph with my kids on the tube.

If for now I just wanted switch drives, does switching to a Bravo require engine removal?

[marshmat]

Hi STP, and welcome aboard

From the current Mercruiser literature on the Bravo 3:

Single or twin applications up to 65 mph for gas engines up to 525 hp

But then their spec table says:

Bravo 3 Maximum Power Capacity 400 HP (295 kW)
Bravo 3X Maximum Power Capacity 450 HP (332 KW)
Bravo 3X Diesel Maximum Power Capacity 320 HP (246 KW) - Application Specific, Consult Your CMD Distributor

Which would seem to suggest that your beefed-up 450hp could probably be managed by a new Bravo 3X, but might be a bit much for the standard Bravo 3. It is my understanding that the main differences between the 3 and the 3X are beefed-up shafts and bearings, and some kind of extra reinforcement in the upper gearcase. But don't quote me on that.

[CDK]

Long ago I owned a Glastron-Carlson CV23 with a 350 HP / Alpha-1 package.
It performed perfectly during the whole warranty period. Shortly after that, the vertical shaft snapped.... This was a standard setup, no experiment of mine.

Through the years I learned that Mercruiser data is - at the least - very unreliable. A Mercruiser HP is not 736 Watts, product life ends when warranty ends and a year is not 365 days, just one summer season.

[marshmat]

And that, CDK, is why I have a strong preference for Volvo over Merc when possible.... too bad the Swedish spare parts are so dearly priced.... but even a 20-year-old OMC Cobra would be just starting to break down about now.

[Jango]

If it were my boat, I would decrease HP slightly, perhaps a cam change and install a Bravo 3 or OMC if your current outdrive breaks.
OR, You could always sell the "Big" engine and leave things as is

[rasorinc]

These people make a strong outdrive.
http://www.konradmarine.com/