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-   -   Mercruiser HP 500 supercharged ? (https://www.offshoreonly.com/forums/general-q/173884-mercruiser-hp-500-supercharged.html)

Jammin' 11-24-2007 03:34 PM

I'm putting small (M1) Prochargers on my 500HP's with HP525 cams. MSD ignition, IMCO exhaust and Cometic gaskets. 5 lbs boost or less. I had the Prochargers on hand and Procharger says they'll work.

tomcat 11-24-2007 03:49 PM

Great engines for supercharging. We have dynoed many with centrifugal superchargers and big intercoolers. If you make less than 800 HP, something is wrong. Cylinder pressure and bearing loads have all increased by 60% so upgrades like head gaskets and rod bolts are in order.

monstaaa 11-24-2007 06:26 PM


Originally Posted by RUNNINHOTRACING158 (Post 2346444)
700 is realistic , 800 to 900 not for long and you'll be putting some good parts back in:evilb:

echo,,,,,echo,,,,,echo,,,,,echo,,,,,,,,


and i guess runing hot has has his fair share of experience pushing the envelope.:drink:

Sonic36 11-26-2007 12:21 PM

500 hps do react well to supercharging, but I would be more worried about whats behind the engines at that point, stock bravo drives don't normally react well to superchargers LOL...and might I suggest replacing the factory oil coolers with some much larger ones :D

Croozin2 11-27-2007 09:36 AM


Originally Posted by monstaaa (Post 2346442)
B & M 8:71's

heres 2, first mad about 720, the second made 800.

Monsta, who's Top Gun is that in the second photo with the 800's?

monstaaa 11-27-2007 06:23 PM

that is an 99 or 00 that belonged to a guy from jersey but he kept in south florida during the winters. he has sold that piece about a year ago i believe. dont know where it is now.

Griff 11-27-2007 07:13 PM


Originally Posted by Nicolasticity (Post 2346475)
I have a 454 Gen V HP425 with a B&M 174 - is this block the same as the 500hp and if so does that mean its bullet proof (English expression for long life with abuse!)

The block is different internally. An HP500 is 502 cubic inches and uses siamesed cylinders. Nothing is bullet proof. Some are just better than others.

Croozin2 11-28-2007 07:04 AM


Originally Posted by monstaaa (Post 2350302)
that is an 99 or 00 that belonged to a guy from jersey but he kept in south florida during the winters. he has sold that piece about a year ago i believe. dont know where it is now.

That's what I thought. The boat had an eagle head with stars and stripes on the sides. I looked HARD at that boat but OSO member Schweeng had already struck a deal with the original owner (John Gregorio if I'm not mistaken). It went to the west coast where it was sold again but it still resides there. Did you originally SC those motors? I remember it saying MONSTA 800 on the flame arrester.

markku4444 12-02-2007 02:51 AM


Originally Posted by Sonic36 (Post 2348348)
500 hps do react well to supercharging, but I would be more worried about whats behind the engines at that point, stock bravo drives don't normally react well to superchargers LOL...and might I suggest replacing the factory oil coolers with some much larger ones :D

Hi i have a pair of Speedmaster IV behind the engines so i belive they will hold.

monstaaa 12-02-2007 07:26 AM


Originally Posted by Croozin2 (Post 2350927)
That's what I thought. The boat had an eagle head with stars and stripes on the sides. I looked HARD at that boat but OSO member Schweeng had already struck a deal with the original owner (John Gregorio if I'm not mistaken). It went to the west coast where it was sold again but it still resides there. Did you originally SC those motors? I remember it saying MONSTA 800 on the flame arrester.

indeed, those are some more children of mine i have set loose to the public.:drink:


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