I ran a 3.5 psi ProCharger for 4 years & 200 hours on a 496 Mag.... no ECU reprogram.... NO PROBLEMS EVER! And the motor is still running perfect for the new owner today last I heard....boat went from turning a 24 Bravo one at 4900 rpms to turning a 28 Bravo one at 4900 rpms... nothing changed in the mannerism of the 496 under 4000 rpm's... once into the boost, over 4000 rpms... everything changed... including the gas mileage!

I wouldn;t hesitate a minute to procharge a 496Mag 3.5 psi.... remember Mercury used to warantee their 525SC for one year back in the 90's with only 3 lbs of boost.... 3lbs won't hurt a thing on that motor.....

My 496 was rebuilt to be ran with the PC. All forged internals, balanced and blueprinted. SS and inconel valves, upgraded springs, blower cam, bigger injectors, PCM programmed in boat while under way. It now makes totally reliable power and I am not worried about calling on it. Also still get good fuel milage at cruise. My 34 prop will push up to a best of 102 MPH and that is only at 4.5 lbs of boost. I could go a bit more boost if I wanted, but I'm happy with it being totally reliable. Downside is that it cost a lot of $$$$$ to totally rebuild the motor to these specs.

JB

I wouldn't boost anything without forged pistons. Just my opinion though.

I totally agree!

i read somewhere that you get approx. 25hp for every pound of boost...3 pounds on an ho would get you around 500hp...not too bad,i guess

3.5 gets 580hp on a ho. The25 hp per pound of boost is after the first 3. the 5 psi kit makes 625.

For those who are lucky enough to run stock block mercury 496's with superchargers even those at 3.5 lbs of boost, no ECM reprogramming and have no issues from the engine you have joined the lucky 10% club and all the best to you. If you don't care for 10/90 odds then I would beef up the rotating assembly before you go there.
Just my professional opinion, but what the heck do I know ?

Best Regards,
Ray @ Raylar

I don't believe the 1 in 10 odds...... but I'm sure you see the ones that don't work out... and never hear from the ones that do....

so true,and same here...i only see the exploded harleys...

thanks...you just gave me 50 hp i didnt know i had !!