WETTE VETTE, you are right, blowers are even worse. More boost causes more exhaust and even more problems.

On the dyno our 557ci SC motors made 6 less HP using the Merc Gils over a set of Stellings.
From what I've seen...you could run the stock manifolds on a Whippled or ProCharged 502MPI.
Dean, What heads you runnin?

Back4More
 

i don't actually have them yet, total marine performance is building the motors now. but here is what stephen from totalmp said they will be.

I would think that one would'nt need to touch the ports on the Canfields...From want i saw they look good right out of the box, but Im no expert.
We just droped on our 350cc Canfields.
Anyway with your 540 I would run a performance exhaust like Gil or simular.

4 more,
Pro Junk, huh? :) lmao

Yeah...I really shouldn't have wrote that.

Dean, I would go with CMI E tops, Imco Power Flow Plus or Stellings. Exhaust is important on supercharged motors, but most stock exhaust systems are fine. In supercharged applications, the air is being forced through the engine so the best exhaust is the one that flows the best in most cases, there are scenarios where there is too big and too small. Example, 502 magnums with sc, exhaust such as the cast manifolds, tubular headers all made anywhere from at most 10 hp, the ones that made more hp dropped the boost because there was not as much a back pressure. Now, more restictive exhaust doesn't make less hp, it creates more pressure which creates more temp which can lead to less hp. Example, run dyno, 6lbs of boost, whatever exhaust, switch on quiet system, run through propshaft. Boost jumps up to 7, power stays the same. With a supercharger, the cfm volume will somewhat dictate the power level. I've had motors with brocken rockers, etc. put an extra 4-5lbs. of boost into 7 cylinders and one none, and still make very close to the same power. Ideally you want the best exhaust so you lower boost, but then put it back by increasing mass air flow through the engine vs. just increasing pressure. It gets mose complexed because of detonation, temps, air density, cam design, etc. but thats the jest of it.

Naturally aspirated can be very critical because it's used to "scavange". This means, it tries to create a vacuum to suck the air/exhaust through the engine to increase air flow. An exhaust system that scavange's more increases air flow subsequently increasing potential power.

The tubular headers work the best, CMI's are great, as are Stellings but are more prone to leaking, cracked welds, etc. The cast aluminum manifolds are not all created equal, Imco's Power Flow Plus work really and typically make almost the exact same power as tubular CMI's on the dyno with big motors. So if you went with either of these 2, you couldn't go wrong.

Silent choice is fine to use, especially for idiling around and slow cruising. Just never run WOT because at the power range your talking about, it will probably increase boost 2-3 pounds and will raise combustion temps over 100 degrees. But there should be no problem for cruising and idle around the docks. Imco's "Gatling" mufflers make the motor really quiet if thats what your looking for, I have them on my Hemi's and there really quiet.

Thanks,
Dustin

My experience has shown me that the faster you get the exaust out the better. An example would be with a project I had last year with a 890hp blower motor. The boat was bought with eddie marine thunder exaust. We switched to CMI tubular E tops and gained 2 mph. $6800 to go 2 mph faster. I think the money could of been used for somthing else to gain more speed like a shorty drive. I guess this shows me that the eddie marine thunders are a good manifold.

You guys ever heard of water reversion? Every engine builder in this area refers to silent choice as, silent death.

Team Gary
 

those are the concerns i've heard most of. can you, or someone else go into detail on the theory of how reversion is caused by super chargers coupled with silent choice? my understanding has been that one could pretty much remove the possibility of reversion by cam and exhaust selection. to me, it seems as though higher exhaust pressures produced by forced induction would, if anything, help prevent reversion.

dustin, if i specify that i want to run silent choice with my whipple charged motors, can you select a cam that will prevent revision without sacrificing too much performance? or how much would hp actually suffer in order to gain that assurance?