Who has the best pricing on these? Are they a direct bolt-on? Is the stock thermostat housing retained?

Thanks,

Kurt

Kurt-

What are you up to now ???

Dave

Hi Dave,

I'm in the process of freshening up a pair of 575 SCI's for a 30' Mystique. The stock Merc intakes have some corrosion around the water passages. Since these motors now have flat top pistons (stock are dished) we are thinking of adding the Whipple intercoolers that are built into the intake.

Are they worth the money if we are going to keep the boost at 5 lbs?

Kurt

I left a message today, waiting for a call back.

Kurt,
You will actually pick up a small amount of H.P. and you can also bump the timing a little bit. If you wanted toget a smaller pulley and go to 6-7 lbs, those motors will really come alive and you won't have to worry about detonation at all if you keep the timing stock.

Personnally I would never run a blower without an intercooler. It adds so much more safety margin plus a nice Hp bump.

Talk to Dustin and he'll give you the straight facts. I am changing to aluminum heads on my 502's and then going from 6 to 8 lbs of boost. I was going to build the motors but they are starting to check noise levels in IL and I don't need more problems. The boat is semi quiet in stock form, and I like it that way. With 8 lbs boost I should be around 700 horse each.

From what I was told if you add the Whipples without changing the pulleys you will lose hp. You can gain it back and more by changing the pulleys but will the gains be worth the strain on the drives.

I'm having my 575 SCi's rebuilt to last and will pickup about a 100 hp from all the good stuff that's going into them. Very good sources recommend that I leave the intercoolers off. I'm going to run them for a year first and if I'm not satisfied I will put the intercoolers on later. The XR's will be beefed up too.

Don't get me wrong, I'm a big fan of Whipple ( I have his blowers on my 454 mag's in my Checkmate and love them) and if my 575's were still stock and healthy, I would put them on them.

just my .02

Guys,
I've done this on a freshened up (new rings, Felpro Gaskets, bearings) 575. I had previously installed the Arizona Speed and Marine boost kit.
The stock blower pulley is 4", the one supplied by AZ S & M is 3.5", along with a reprogrammed ECU and MSD 6M spark box.
I did loose a little boost due to the additional plenum area of the intercooler manifold. Even with less boost (5.5 lbs), the motor was absoloutly on fire, so this combination is working. I have since installed a 3.25" blower puller to get my boost back to 6/7 PSI, which should really make this setup rock. I also have 3" pulley for special occaisions.
If you think about it, this is the perfect application for an intercooler. A relatively small blower on a fairly large displacement motor. You have to spin it fast to make additional boost, and that makes a lot of additional heat.
You can read more on the Nordic owner's forum post "best prop for a 28' Heat". I also recommend Bob L and FTM for the intercooler and advice. He's the real deal. By the way, this is more complex than just a bolt on, as you will read, but it's worth the effort in my opinion.
Regards,
Steve

Just fyi, Steve, you didn't lose boost because of the plenum size. You lost boost because the charge is cooler and more dense, the blower is still feeding the same amount of air until you change a pulley. You have not changed the mass air flow that the engine is seeing. Boost is a direct relative of heat. You have increased the quality of the air by cooling it, also making the combustion process easier to control. Now, when you change the pulley to get it back up to 6-7 lbs as you stated, you will have drastically changed the mass air flow that the engine is seeing. Of course the efi needs to be remapped accordingly...fuel and/or spark. Again, just food for thought.

Talk with Cattude on OSO.
He also did a 575.
I think he also sells the Whipple systems

Yes he does. I talked to him about them before.