diggin H20

I have read many forum posts but this is my first one so here goes. I am looking to add some performance back to my 1999 Powerquest 280 Silencer. I have a 454 mag, 385 HP, stock motor w/ K&N filter, 24P Bravo One prop. I am running 4900 rpm max. I know I have lost some speed and hole shot by adding alot of weight. I added A/C, stereo, tv, dvd, and a some other misc. items (comforts of home you know). I have seen several exhaust options but don't know which is best for the performance and or money. Revolution Marine seems priced right but is Stainless Marine or Imco worth the extra $1000 plus. If so I will buy it. Pros or cons on this or any other suggestions would be appreciated. I don't want to tear the engine apart or supercharge it. Also saw the EMI thunder exhaust, and by the way I have the corsa switchable exhaust system.... Thanks!!!

Payton

Simply adding the exhaust may or may not give you any more power. But it will help any other upgrades work better. There are guys that are very happy with their RM manifolds that are putting out over 500hp.
Do a search on them

MC-BOYS

We have a 99 Powerquest 260 with the same engine 454 Mag 385 horse. Last winter put the Imco powerflow exhaust on and it sounds awesome. The engine was completely rebuilt so I can't tell you about performance changes since it ran like crap last year but sounds and looks great and no prob with the Corsa hook-up. Engine is now running around 450 horse with engine upgrades and exhaust. Did I mention how could it sounds. Everyone at the marina stops when we fire it up.

diggin H20

MC-BOYS, What upgrades did you do to your 454? Where did you purchase your Imco set from and how much did you pay for it? Thanks

diggin H20

Anyone know where the best place is to buy the IMCO exhaust? Discounts for OSO members? Thanks!

Griff

You will probably see more performance from the weight saving of aftermarket exhaust than the actual exhaust itself. I would just go with the Revolution Marine exhaust.

suntimes

I added EMIs (aluminum top) to my ' 99 454mag MPI and gained 2 mph. I also have corsa switchables and the mod was straight forward with the remount plates for the linkage and computer. I had to bend the oil filter bracket up slightly to clear the manifold, otherwise it was a straight fit. I could feel an improvement coming on plane (the weight savings probably helped with that) and the motor also sounds better.

I added a fuel pressure reg at the same time and tried raising and lowering but the factory setting ended up as the best gain. I also modded the flash suppresor to flow better and gained 1/2 mph.

With the prop you have now (and weight you added), the exhaust manifold change might be perfect to get you back to where you were.

TwinTurboStroker

Revolution Marine..

+ 1

BURNSMAZZ

I put Gils on my 454 mag in my 25 Outlaw I wouldn't waste the money on a stock motor .02

tlingen

I just received a new set of Revolution heads for my 99' 454 385hp today. They are way lighter than the stock stuff that's for sure. I wont have my boat out for another week to tell you how much they helped me. I'm waiting for parts to finish replacing my gimbal ring and seal.