lotoparty
If you know Doug Feisk(sp) in Lee Summit. He may have a ProCharger that was used very little. The guy knows his stuff about installing ProChargers and has installed several in the area.

You can retain your stock exhaust with the Whipple.

Don't bother with exhaust unless you're going to do some head and cam work. Previous boat had a procharged 454 mag - swapped the stock exhaust for IMCO powerflows and saw no increase in speed or RPM. Did sound better and look cooler though.

Let'r BREATH and watch'r BUCK!!!
 

Before a marine engine can really realize a power increase it needs an exhuast system that breaths better than Merc's cast iron, VERY crude, stock exhaust system! If you put a blower on an engine with a Merc stock exhaust system, YES you will go faster. But if you really want that thing to perform it MUST breath well!...and anytime you install a supercharger on an engine it is how the EXHAUST is set up that will make the BIG difference! Exhaust.....Exhaust....Exhaust!!! If you can only afford one thing right now install a decent aftermarket exhaust system on it---Stainless Marine or Gil is at least good enough. You may not pick up more speed or HP, BUT from there on if you add any performance parts to the engine it will respond to the parts you add because you added the exhaust first. I'm not an authority on the exhaust subject, but I can tell you this from several years of experience. Best wishes

Re: cheapest way to increase hp on 454 mag
 

Merc part # 37-861314 33 $22.85 (502 Mag decal kit)

Kaama, exhaust on the supercharged 454/502mags can be a huge waste in most cases. For the standard 6lbs, the best exhaust system such as CMI's or Imco Power Flow Plus will increase power approx 8-10hp while others while some will actually lower HP output. Although the stock exhaust is crude, it still flows quite a bit. Once you get past 650 range, it's starts to get somewhat exponetial. SC'd motors are very less critical to exhaust and HP. So bang for your buck, SC is the only way to go. Doing heads, cam, ECU, exhaust will get just as expensive but won't touch the SC'd motor. If you stay NA, then you have to put exhaust on because they may flow ok, but they don't scavenge well.

Kokopelli's right, you should be able to find some of the used side mount systems for around $4000+ range. I know of 2 right now that are in really good shape if needed.

This is similar to the 496 motor, but even more of a waste, the stock headers are much improved over the sender block style and basically, only CMI makes more power and even then, I can't see spending the money because it just doesn't compete with the SC. It is somewhat funny though, I can tell people this, and then afterwards, there like, and so what MPH increase should I see with those? :D So if your on a budget, exhaust would not be the best option on this particular package.

But even though it doesn't really make more power, they sound WAY better, are about 10,000lbs lighter and look better, not sure what was going on with the square exhaust package. You know it's been proven, sound is worth 50hp :D

Thanks,
Dustin

Tomcats dyno test says it all, 415 hp increase with a vortech and his intercooler box! That oughta do it.Greg

:cool:

The whipple or -procharger is the way to go for that much speed !
Or run a 250 b&m or holley blower they work great if you have room and are cheap!

I'd save money until I could install some type of blower :D :D