357 Mag Bravo 4 Enough???

[FloatingCamp]

I am looking to buy at Doral 270 SC, 8'6" beam, 7,100 lbs dry, with a bravo III drive and want to know if a new repowered mercruiser 357 Mag Bravo 4 is enough motor to get this boat on plane without stressing the motor and dragging the boat 1/2 a mile before standing her up. It was originally equipped with a merc 5.7l 260 hp motor, that I believe had more torque (even though less hp) and I wondering if this new motor is sufficient for this size boat?

Thank you for your time and feedback. Greatly appreciated.

[GordMay]

Greetings and welcome aboard the CF, FloatingCamp.

[dave948]

383 seems to be a popular replacement for the aging 454 based boats, close to the same torque and HP.
Go too small and you'll regret it.

[FloatingCamp]

That's my worry, ie regret. Especially with a big purchase like this. I wish it was the 383. Seems like a better motor. Also wish it was fuel injected. Feel like with all this doubt, I should pass on the boat, even though it is perfectly cared for and maintained.

[blackcrow]

I know it is not the same but couple of years ago I had boat 20'10" x 6'22 with FNM HPEP 250 and bravo 3 X diesel, instead OEM propellers I put four blade props from hill marine and boat wit full tank and three (European size) persons on board went on plain almost from standstill.

[jimbunyard]

Assume you're talking about the 325 hp version. Given the original was 260 hp and that you have a Bravo III outdrive (more efficient than single props) , probably most important is that the boat has the correct prop set. Many people want to wring the most speed out of an engine, and install props with too much pitch and/or diameter, which absolutely affects time-to-plane, especially with a boat with as much superstructure (wind resistance) as this one.


Propped correctly, the engine should be quite adequate, with no durability issues, providing you're not trying to get 50 miles an hour out of it....


As far as the carb versus fuel injection, there are pros and cons either way, reliability, cost, fuel economy.


And back to props, prop set needs to be right, because to change them is 700.00-1000.00 (in stainless anyway). Can you not give it a test run? Engine should turn up to at least 4600 rpm with full load (4800-4900 would be better), if not it's overpropped and the selling price should reflect the cost to reprop it, or you will have durability issues.