BRUCE SEROFF

Its a imco 2" shorty. And I believe it helps. Cant say how much as far as speed increase though. Right now Im running a stock XR lower with a 1 1/2 spacer. Works pretty well too.

Jmemoli

iTrader: (1)

Bruce ,
You should have learned by now that most people do not post their real speeds .
It may be too embarrasing for them .

Von Bongos' boat did 74 is at 4700 RPMs' . The motor /boat combination could not pull higher rpms' .

I have yet to see many boats like ours running over 80 mph.

jsm

Von Bongo

Actually it was 4900 RPMS

Von Bongo

496 = 425 at the prop
575 = 550 at the prop

Cattitude

So merc black tells it like it is, the boys in blue like to bench race

...But I've got them sandbaggin now

Von Bongo

Mercury Mercruiser engines
Gas Sterndrive HP 575 SCI 550 hp

It’s a first for Mercury Racing® The HP575 SCi pairs a custom supercharger with fuel injection for greater power and control. You’ll enjoy turnkey starting, smooth-shifting, instant throttle response, and a very broad torque band throughout the engine’s operating range.

Boating Benefits


The MEFI 3 Electronic Control Module, which provides precise fuel and spark control and unmatched top-end throttle response.
A top-quality valve train designed for improved airflow and durability.
Custom-forged aluminum pistons.
Heavy-duty GM® -forged crankshaft.
Custom 256 CID Holley/Weiand Super Charger, matched with a state-of-the-art throttle body fuel injection system, that provides sport boaters with turnkey starting and offers enhanced idle air and spark control for easy docking and exciting driveability
A thermostatically controlled, high-capacity oil cooler that raises engine oil temperatures faster and keeps them more consistent.
The oil thermostat and a Positive Crankcase Ventilation (PCV) valve that work together to reduce buildup of condensation in the oil. The PCV valve also improves engine idle.
1-year limited warranty.
Bravo One XR drive.
Exclusive Mercury MerCruiser® service dealer network
*GM is a registered trademark of General Motors Corporation.

It must be a new thing I see them doing it with all the blue motors now rating them on their crank HP. They used to to it at the prop. Maybe it is a way to charge more for the engine . But probably just to avoid confusion.

575 sci = 550 PHP
525 (old supercharged 454) = 490 php
500 EFi, 500HP and 540 Bulldog = 470 php.

As for speed, I would say 64-65 with the right prop and load in fresh water. 62-63 on most days.

bad boyz

I THINK THAT THE 525 HP MOTOR HAS MORE BALLS THAN THE 575 HP PUT THEM SIDE BY SIDE IN THE SAME BOAT AND YOU WILL SEE THAT YOU ALL WILL BE SURPRISED.
THE 28 PANTERA IS ONE HELL OF A BOAT NEVER HAD ONE BUT HAVE SEEN THEM AT THE RACES A TRUE OFFSHORE BOAT TO SAY THE LEAST.TO GET FAST SPEEDS YOU NEED BIG CUBIC INCHES AND HORSEPOWER EVERYTHING ELSE IS JUST STANDARD EQUIPMENT.IT IS NOT HOW FAST YOU WANT TO GO IT IS HOW FAST YOU GO A LONG WAY WITHOUT BREAKING DOWN.YOU CAN USE A BOAT AND TWO PEOPLE TAKE IT OUT AND THE MORE EXPERIENCED DRIVER WILL GET AT WOT MORE SPEED THAN THE ONE WITH LESS EXPERIENCE.IT IS NOT ALWAYS THE BOAT IT IS THE PERSON WITH THE STICK AND THE BALLS TO TAKE IT TO THE NEXT LEVEL.SORRY IF I HURT SOMEONES FEALINGS
BUT THE TRUTH IS THAT NOT EVERYONE IS CAPABLE OF GETTING THERE BOAT TO ITS TRUE LEVEL OF PERFORMANCE.TWEAKING AND TESTING X-DEM, A TRUE MOTOR RUN AND TESTED AT A DYNO THE PERFECT COMO AND PROPS GETTING YOUR BOAT BALANCED AND WEIGHED,WHEATHER YOU RUN STEP HULL OR NOT TO GET SPEED YOU NEED POWER.DAVID

MIAMIBOYZ

Bad boyz,good topic you couldnt have said it best.
Albert

Buddy OO

cat the whipple kit, what did it include and what did dustin charge you for them thanks

Cattitude

I can't recall the price- less than $500 though, couple pulley's and he recalled my ECU, I drilled my own t-stat. A good bang for the buck