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JP BRESCIA
04-15-2002, 09:02 PM
I have a question and need an honest answer. No better place to get that I'm sure. I have been told by more than one person that I could expect to gain 20-30 more HP by switching to Stainless Header-style exhaust from my stock log-style manifolds. This sounds like alot to me. True?

CDMA
04-15-2002, 09:06 PM
Yes, Escpecially with the logs. Those are horrible. Allan Brown is a board memeber and great to deal with. He also works for/runs Stainless marine. He is helping me get set up with exhaust for my new 383. A great guy and from what I hear a top notch product.

Chris

Allan you get my e mail?

JP BRESCIA
04-15-2002, 09:13 PM
Thanks for the reply. I'm glad I asked.

I'm sure I can slice a small bit out of the refund check for her. :cool:

Murphy
04-15-2002, 11:04 PM
I agree with this and think it's important to add that alot depends on your engine setup... horsepower, cam, current exhaust, porting, tuning, etc. Also, terminology wise, the systems built by Stainless Marine, IMCO, GIL, and some others are technically high performance exhaust manifolds rather than true headers. They sort of fill a cost-effective slot somewhere between boat anchor stock manifolds and high dollar headers. By internally separating the exhaust pulses and reducing back pressure, they keep the engine from working against itself much like a set of headers. Result: more available horsepower. No question that high performance manifolds and risers are a big factor in improving performance. Stainless Marine makes some of the best. Getting rid of 200 lbs. of cast iron ain't a bad idea either... boat sits higher in the water, reaches plane easier. 200 lbs. also equates to 1.5 babes and another 12 pack you can take along.

Good Luck,

Murph

CDMA
04-15-2002, 11:43 PM
Murph Murph Murph,

I totally agree but really 200 lbs will get you way more then a 12 pack...
wink :D wink :D wink :D

Chris

GEOO
04-16-2002, 11:23 AM
JP,
What engine do you have? Small Block, BB?? Stock or Modified?? A stock Small block will not notice much power gain. Stainless Marine Exhaust is great, lighter and will last a long time but I don't think a stock small block would gain much. Big Blocks gain alot more. The stock BB exhaust is too restrictive. GEOO

HP 600SC
04-16-2002, 09:07 PM
Between the better breathing and the wieght saved
I think that is very reasonable

BigGrizzly
04-16-2002, 10:47 PM
OCorsican I havetrue hedders by CMI. If they made Stainles Marine hedders for my 351 Ford Clevland I would have bough them instead. CMI was my only choice. HOwever When I replace the ones on the Criterian I will do the Stainless Marine type. My engine is a supeeercharged 502, and that is going to be the choice for me. Besides if they didn't work well Brownie wouldn't sell them

Randy

JP BRESCIA
04-17-2002, 10:31 AM
Geoo. My motor is pretty much stock. It is a 350 sbc 4 bolt(1980 merc 260). There is minor enhancements in the heads/valves that was done last year.

I had a problem last year with my old exhaust manifolds leaking water into the motor thru the valves. The water pushed passed the rings and into the oil. :mad:

While I had the heads off, they went to the machine shop for a tune-up and some minor enhancements. This was the time for me to switch to Stainless Marine but it was mid-season of my first year with the Donzi and I didn't want to waste a few weeks figuring out the new exhaust setup.

Unfortunately, I put new logs on the motor last year. That is part of the reason I am reluctant to switch just yet. There is little to no market for my 6 month old logs I'm sure.

GEOO
04-17-2002, 12:45 PM
When you order the Exhaust have your cam specs for Brownie. If you have a large lift cam, and or large overlap you will need to have custom or special elbow/pipes which dump the water into the pipes closer to the transom. A "large" cam with stock Stainless Marine exhaust would still have reversion. Brownie at Stainless Marine will help you pick out the correst exhaust. GEOO

JP BRESCIA
04-17-2002, 10:12 PM
Thanks Geoo. I have much to chew on.

jengel
04-18-2002, 04:37 PM
This is for those of you with the Sweet 16. Fuggetaboutit. I have a 1976 16' with a small block 350ci/350hp "Corvette" engine. I read all the Donzi.net posts and was convinced that I could get the increased performance you described so I contacted Stainless Marine. They couldn't help me. Nothing fits the 16. It had to do with that reversion discussed in the previous post. It had to do with too little clearance for the elbows. It had to do with too little room between the engine and the stern which would have required moving the exhaust. They proposed to manufacture something for me but in the end I went with what I guess you call logs, made by Garwood for about half the price and most importantly fitting the same very limited dimensions. Note that the location of the thermostats has changed since 1976 and this was a bit of an issue for us. Oh, and maybe I'm a wimp for saying so but in Long Island Sound 65 mph. has been fast enough in a 16 foot boat.

GEOO
04-20-2002, 05:44 AM
Jengel ,
Becarefull of reversion!!! You may be sucking up small amounts of water every time you run. Just alittle will be unnoticable until you have a valve failure.

I have always had great service and have found Stainless Marine to be very creative, helpful, and knowledgable.

I live in Fairfield, CT and do most of my boating on Long Island sound too. It sounds like you have a nice 16, would like to check it out some time. I run an X-18. She should be ready for the first run of the season today. Hopfully I'll have sometime soon to run her soon. Is your 16 ready ?? GEOO