I had no idea.......
 

Sounds Awesome-! Id love to see picts and dyno sheets with both sets of exhaust back to back.

I wonder why...

Sterling, Teague, Ilmor, TPI (Gary Taylor) Potter, Gellners, Ateco, Mercury Marine, and every other high performance builder in this business - spend the extra money on tube headers when they could be saving 2-3K a motor with manifolds then.

A lot of prestigious manufacturers prefer tube headers- for a reason.

I find it odd that Ilmor would choose to equip my new 710 with an exhaust system that would be 15 HP lower and cost 3K. more?

Why didn't a company thats won-

13 Indianapolis 500 Wins
184 Indy Car Wins
165 Indy Car Pole Positions
10 Indy Car Drivers Championships
5 Indy Car Mfrs. Championships
And
2007 and 2008 P1 Powerboat world champions

If that's your results that thats a find- you made more power spending less money than the next guy.

In the meantime Ill stick with what Ive seen and know firsthand.

Manifold type for cost or medium build
Tube for power -

Uncle Dave
Laveycraft 2750 -710
Laveycraft 20.8 Sebring

The Stainless High Torque III have runners ( 22 " long ) befor they meet. Just like or even longer then most Headers. Oh,,,,,and the runners are most defenetly larger then ANY Header !
Also you can get them with a 6" dry pipe, most Headers only come with 4,5 / 5 " !!!!!!!!:eek:

Those look pretty D - good
 

DareDevil- Those are probably the best manifold type exhaust Ive seen and the longer runner will make it perform better- on this one though it looks like you lose the ability to rotate the top like the small runner version.

The Dana Marines have long runners for a manifold type as well.

This is a pict I took right from the Stainless marine website showing just how long the runners are.

The other pict is a long tube header pict taken from CMI's website.


Uncle Dave

Laveycraft 2750 -710
Laveycraft 20.8 Sebring

Uncle Dave,,,,, your right ,,,,,it looks longer ,,,,,but if you cut them open the waterjacket around the inner tube is smaller volume then the SM HT III .
Also if u consider the weight, NO daubt that the SM is alot lighter and alot cooler too.
The only plus the CMI gets is the look and the maybe longer runners.
I have the SM HT III on my boat and i know for a fact its no power loss compared to the CMI or any other Header !

SORRY. :ernaehrung004:

Not for small blocks- .....where can I find....
 

This is a great post and I'm learning about new products- and hence have some questions.

Did you dyno test the 2 seperately? Or take a set of CMI's off your boat and replace them with SM gen III's ? Im curious as to what your firsthand experience with both is. You have picts?

I notice that they aren't made for small blocks so the original posters doesn't benefit from this product, but is stuck with 2 choices- the small runner product, or a tube.

No doubt its a trick manifold for sure- I dont think its fair to compare it too a smaller runner systems available for small blocks and say they are the same

So when I said "they have tiny runners" For the small block product that is 100% correct.

SS Gen III is awesome, and does deserve to be directly compared to headers- this is a different discussion but applicable to the small block question.

It seems you are making a direct connection with horsepower and runner length and size which I would agree with (on a really high perf engine) I still say for a medium build it doesnt matter.

DO you think the ID is the largest , or do they actually state that?
(for a manifold system it might very well be the biggest Ive certainly never seen a manifold this good)

I see they have tails for 4.5 & 5' pipes- but where is the ID mentioned?

Is there a measurement of the "primary" tube? Or a measurement till they all dump together? Where is the inner diameter actually measured?

I think its a fair guess to say in the manifold piece is pretty big but when its moves to the secondary piece that bolts on top- all 4 get squished down pretty quickly at the point where the "primary" measurement ends.

Why cant I find an ID measurement on their website? I may not be looking on the right place. Im intrigued by these and think they offer the best compromise ive seen- but Id still like to see the numbers.

IF you look at the CMI site you'll find that they sell the long tube and race headers by the inside diameter, and prices go off the chart for the huge ID race tops.- as much as 9K

Why are companies with millions in r&d to spend that have in house dynos spending the money if they dont have to?
For looks? Or are they just stupid and don't know what you know?

The savings for these companies would be dramatic as I can get the gen III's for 3400 a set. (personally I think this is a GREAT value for what they offer)

You're probably right on the weight as two cast aluminum pieces with the SS bolted to the top is probably lighter.

Running cooler-? I see no evidence that that is anything other than a guess. Why would it run cooler? I don't think there is an intrinsic problem with either design so I don't see why its an issue but Id still like to know why you pointed it out.

Brand loyalty is a powerfull thing that can lead at times cloud ones judgement, but.......

I'm open to getting schooled for sure-especially if it means I can the same or better result with half the money spent- but in all honesty Ive never seen that work anywhere but in the pits after the races or when people are talking about results vs actually achieving them.

Ive seen no actual evidence of a free lunch here.


Uncle Dave

Laveycraft 2750 -710
Laveycraft 20.8 Sebring

Another vote for stainless marine, I have them on a newer 6.2 picked up about 80-100 rpms and lost 83lbs on a single engine set-up over the factory merc stuff. Steve

"Header Wars"
 

On the subject of Big Block Headers Exhausts-

Are you absolutely sure they are bigger? Looks pretty close to me....

I think it is fair to say that the Imco runner is without question longer as it's 100% of the length of the "secondary manifold" and its 1K cheaper.

It's impossible to determine flow on the rectangular curved pieces on either, but in a length of primary discussion-

The pict above is boostpowers 1000 all aluminum"superlight" big block.

Ill still take the true header over either.



Uncle Dave

Laveycraft 2750 -710
Laveycraft 20.8 Sebring