Opinions On Exhaust
 

Looking to put performance exhaust on brothers boat.
I've been online & read little on the different makers.
But was wondering what people have to say that used them,
what brand they used and what improvement if any.For example, CMI vs IMCO vs Eckert vs Stainless or DANA

The motor is a built 454 don't remember exact specs right now but has stroker crank ,bigger cam, higher
flow intake. But still has stock exhaust/manifolds and told adding perfromance exhaust would help quite a bit.
The motor was rebuilt by Wilson's Marine took a 93 liberator 221 from 55 to 66-67 no bs. Wilson's has recommendations that I believe. But just wondering about other boaters improvements. Oh yeah Wilson's was great. answered all ?'s
made recommendations .Boat runs better than ever

Look into the EMI's ...they were good for the price.

The EMI's are cheap and they seem to stand behind their product but I've seen a few sets fail recently and I'm not very impressed...

I still stand behind the workhorse, Stainless Marine!

Its already here, do your searches!
 

Check the forum previous threads here on exhaust and headers for marine engine, there is enough info and comparisons with feedback from sellers, users and others to fill a set of Encyclopedia Brittanicas !!

Best Regards,
Ray @ Raylar

I have a 221 libby with EMI thunders on stock motor sounds great. Used to get 51mph with a 21 stainless. Put a 21p stainless tempest plus from merc blades on and brought it up to 58mph. good blade for this heavy boat

CMI Unitops are a great bang for the buck if he has standard Bravo exhaust holes. http://www.custommarine.com/headerapps/ElbowTop.php

stainless marine gets my vote. go with the dry setup.:drink:

mrfixxall
 

Emi's,,been running them for years..Best bang for a buck in my eyes..i solt many many sets and never had any issues..

Did you want mainfolds or headers? Do you want to look stock or do you want bling. Some power or the most power? Go with CMI

I say stainless marine.,,,had them on mine for 8 years in salt water and never any issues...

If you are going to spend money on looks and performance why buy manifolds?

CMI E-Tops or Sport Tubes are headers with style and performance. Ask about the CMI Unitops as they are priced nearly the same as the other guy's manifolds.

manafolds
 

i have used both stainless marine and emi,s.i just bought a set of emi,s this year.very happy and the warrenty is the same as stainless marine,but cheaper.i bought my emi,s from diamond performance.they are advertizers on here and have great prices,and great service.

if you're interested i have a set of emi with custom tailpipes for a good price. about 2hrs on them

Stainless Marine.

Cmi

mrfixx
 

Stellings:Score-101010:

Welded tube headers look the best but cost the most and have a history of developing cracks over time which results in water getting into the cylinders and then hydraulic lock engine damage if not diligently leak tested and repaired when the cracking occurs. CMI's are consistently mentioned as providing the most hp. You only get the rated hp improvement if you run them dry since wet exhaust increases back pressure.

I opted for the Dana Torque Flow exhaust manifolds which are roughly similar to the KE aluminum header dedsign approach ie extended individual internal runner length. The Dana's cost half that of CMI's and with them one does not have to worry about cracking and associated leak testing to monitor for same and repair. They do not provide quite the hp that a set of CMI's would but close enough given the other benefits.

My 0.02.

Eddie marine are a very nice set up with the stainless risers and perform just as good has the rest and come with a 5 year warranty.
http://www.eddiemarine.com/techsuppo...502_5483_3.pdf

http://www.eddiemarine.com/techsuppo.../warranty1.pdf

Because they actually last and don't cause you to spend more money on blown engines when the headers fail. :drink:

:drink::drink:

right-on.you give up some h/p with manifolds v/s headers,but manifold do not seam to have the problems the headers do.

I have a set of EMI with custom tailpipes which i will let go for a reasonable price.

I run the KEs and love them. They are the best of all worlds. Manifold in structural integrity, stelling tube header performance. An exhaust system needs to have a minimum of 32" indvidual runner length to classify as a "header". It is this length in runner along with collector design that scavenges power. A look at most manifolds (and etops) will show you that they are short runners and therefore will give marginal perf increase, although some over stock cast iron.

Very happy with my KE's.

A real good header manifold
 

KE's cast header manifolds are awesome units and they make great power 40-50 HP on most n/a big blocks.
Not sure of the cost of them now, but they are definitly stronger in the long run than CMI's and they can be powder painted in great colors or polished.
On 496MAG -HO engines it will require some special brackets and remounting of the remote oil filters, power steering bottle and ecm brackets and such but it is do able. As always Kieth makes great parts.

Best Regards,
Ray @ Raylar

I vote Dana. They are the best bang for the buck. I have done many installs with that product & have yet to have one come back.
You can find them out there for $1650 or so for complete sets.

Is that the same Wilson's in Bay City, MI that did the work?

Yes it was Wilson's in Bay City, Mi.

I have had work done by them before and they seemed a bit slow. I am wanting to add an extension box this winter, would you recommend them for that?

Yes they were about a month past the est. time of completion.
He told me mid July and got it back mid Aug
But I took it to them in June so I figured it was a bad timing on my part for wanting a quick turn around time for what I asked him to do but everytime I went up there they
seemed busy. I probably visited the place 4 times too talk and pay Andy and each time they all seemd busy. I paid an intial "down payment" to get started and 2 futher installments after that(my suggestion not theirs) He had different projects going each time meaning the boats that were there when I first went there were not there the next time and other boats were parked or being worked on. As far as the extension box I would ask him.
I'm a basic DIY'er : change oil, sea water pump, out drive lube
but when it comes to modifications I ask people that do it.
I would say if he says he can do it, taking to him in the winter
is best.
He made suggestions about the ignition and carb. He simply stated he did not agree with how it was setup and explained why. I replied do what you think is best. The driveabilty increased 10 fold. Boat starts with out pumping throttle
Idles like it was stock. Which it did not that after the 1st build.
Heck it would not Idle well enough to back out of the dock w/o stalling after warming up at dock for 10 min. Now idles great.
Only my 1st job I asked wilsons to work on. Made a heck of an impression on me. I,m taking my 87' 211 liberator to him this winter
Basically yeah I trust him and the crew. He seems to explain why he does what he does and make suggestions of what to do and not to do. As opposed to some that reply in a condesending tone e.g. "WELL WHAT
DO YOU WANT IT TO DO". I know this was long and there is even more I could tell but I think you get the pic.
Good luck with the ext box.

up stainless marine 4'', I have a pair of dry set up good for big cams 1200. art 617 833 3327, going to a bigger set 5'' for new 572 Dean Gellner blower motor.

SO TRUE, my buddy has a 2nd leak 2 yrs in a row on his etops, but there about 5yrs old:rolleyes:, if its bad hes got a line on hardin marine headers with the black top like a gil top header bottom.:evilb: ugly. you need to drain and rinse your cmi headers which he was not good at.

I had a similar project on my previous boat and I went the the IMCO, PowerFlow system. The exhaust was reasonably priced for high performance exhaust, had great performance gains and sounded incredible . Good luck with you choice.

Ray,
I actually wanted to use the KE's on my 496HO and was told that the KE's would only fit the 502 type heads. I went with the Dana Torque Flow manifolds instead.

So the KE's cast header manifolds will actually bolt on to and properly align with the exhaust ports of a 496HO heads? Is there a special gasket required to seal the KE's to a 496HO head?

I noticed in this thread some consistent pros and cons of headers vs. performance manifolds, ie headers make more HP and manifolds are more durable. I was under the impression that a good performance exhaust manifold will make better TQ numbers than a performance header. Is this true? I have Stainless Marine manifolds on a 454MAG w/ a Crockett cam upgrade and I have to say the boat sounds and runs strong for a 454.

Most standard performance marine engines that are normally aspirated will always make more torque with longer exhaust runners or tubes and they will extract better and generally make more power if the individual runners are in the 20" to 30" equal as possible lengths.
Most of the aftermarket performance exhaust manifold systems are short runners 6"-10" runner length and even though they are much better than the old log type manifolds (pre 1996 approximatly) Merc and others used to put on older big block and small block marine engines they will not make as much power or torque as the longer runner or tube length headers or header manifolds, where the runners are longer and merge into an actual collector either just before or in the risers, such as Dana, KE, Imco and the tubular header systems like CMI, Hardin, Stellings, Lightning and others. Its also important to remember that different exhaust manifolds and headers have different reliability, life and structural differences that must enter into the comparisons and selection process to pick your best product for your application.
As for the KE header manifolds, yes they will fit the 496 head, but there are no provisions for a kit where the oil filter bracketry and other ECM bracketry and such is provided , so you would have to customrework or make special brackets and remote oil filter accessories and such to use these on a stock Mercruiser 496 or Volvo, etc.
Also some aftermarket header manifolds such as the KE or Imco Power PLus header manifolds may in some cases present height problems for overall heights with respect to hatch and engine lid covers for some boats.
I keep saying to clarify! Headers and Header manifolds are HEADERS & performance exhaust manifolds are MANIFOLDS!, there is a difference! Please inform your self with the differences and make your decisions carefully based on your budget and needs & performance results wishes! And also rember that generally its "Different Strokes for Different Folks!"

Best Regards,
Ray @ Raylar

Ray, Many consider you the marine professional that knows more about the Merc 496 (8.1) motor then anyone. Tell us this, have you tested a set of KE cast headers on a Merc 496 motor? If yes, what was the result.

This again.........
 

Ray and Larry build a great engine, and their kits are superb. Their advice is worth paying for so getting it for free is a privilege.

If you can stretch for the headers then do it,
CMI, lightning and Stellings all make a great product.

If you cant I'd look at the imcos or the danas,
I and many others have had great long term luck with the imcos.

Stainless Marine has a good rep as well.

EMI?

Do a little poking around to see what various builders say - most particularly Eddie Young about the EMI's reliability.



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