For just cruising around, the 408 will be torquier (sp?). But in a stoplight to stoplight race with a 500hp 347, you are going to shift at 7,000 rpm and beat the 450hp 408 every time. Especially in a 2,300 lb cobra where torque is not an issue.

If you are doing any kind of racing or performance driving you would bring that 347 up to 7,000 or why would you have built it in the first place. It will always win. But if you are going out to dinner or to pick up your dry cleaning, you obviously will drive it mildly and not have the lower end torque of the 408.


.

No... I thought you were talking about flywheel to rear wheel dyno conversions.

Surely his sidepipes, water pump, etc. are good for 85 horses....%/

Yeah, you're right. Horsepower is horsepower. 500 beats 450. However, if you re-read my statement, I stated that the 408 would FEEL stronger....and it would. You build an engine for a specified purpose. A 347 that peaks at 7000 isn't necessarily going to be street friendly. It all depends.

I always seem to get sucked into hijacking people's threads.

Anyway....

Patrick, are you actually telling me that you carried your sidepipes with mufflers into the dyno room and bolted them on?

Yes. ElMariachi did the same thing. I know it's a bit unusual, but I really believe it's a more honest number, even though it's lower.

To me, it means nothing without turning the entire driveline.

It just throws another wrench into the necessary evil of engine dynos.

Well, you know the difference between dyno'ing with pipes and doing it with open pipes. On a nice big 482, what would you, in your expert opinion, say those pipes rob in horsepower? :p You can just guess, if you want... but I bet you have a pretty good answer.

FWIW, Hall Fabrication, the shop that did the engine/trans install on my car, cut the mufflers off my Kirkham-supplied pipes and used Hushpower pipes, which allegedly are less restrictive/higher flowing. Dave Brown, 4pipes, has the same mufflers on his car. Hall claims they lose less HP.

Oh and my car weighs less than yours . So neener, neener, neener.

Back to the thread.

Ehrrrggg. If true, that's another reason to dyno with your pipes. I had Stainless Specialties build my pipes to be a little quieter (and take away a little more horsepower).

BTW, Hushpower is a division of Flowmaster. They used to be a separate company.

http://www.hushpower.com/

They're a local company and Hall has done a lot of development work with them as well as Redline oil too.

Actually, most dynos have the headers running into exhaust pipes, which go into mufflers. There's a restriction there.

Uhhh, 20 to 25% Please...
 

This seems to be a pretty authoritative post.

http://www.clubcobra.com/photopost/d...0/keith001.jpg

Uh, so, what's your point? There's nothing new here. No new ground covered.

I see something that says sidepipes are the biggest power robbers and I had mine cut off and replaced with allegedly higher flowing/less restrictive pipes.

But you didn't have the numbers checked. That's unlike you to just take a set of numbers "on faith.":p Uhhh, what do you think those horsepower numbers for a 610 engine less 25% turn out to be?:p

FWIW an engine which does not run or is not reliable or as important cannot be trusted is no fun. I like Kirkham reply, keep it under 5.5K rpm's, if you need more power then go more cubic inches. Valve train is the weakspot. The lighter the spring pressures, ie milder the cam, the better the reliability. Speed kills not only people but also engines. I would much rather have 600 ft-lb of torque and 400 hp than 600 hp and 400 ft-lbs of torque. 99.99% I am driving WELL under 100 mph, torque is fun.

zrayr,

Feel free to give me a call. Advice is free. 502.759.1431 There are a ton of parameters and variables associated with horsepower, reliability, and longevity. Again, 5500 isn't a magic number....neither is 5000 or 6000. There's not really a set standard to what will live forever and what won't, but most engine builders have an excellent handle on what works and what poops the bed.

... and it's worth every penny of it.:LOL: Seriously, zrayr, Brent is top notch. If I had known hiim 5+ years ago I would have had him build my FE.

Z,
I really like your car. And I offer my own experience to help you decide the answer to your question. But after that I have to address the rampant nonsense which has jacked your thread. Forgive me-"I can't stands n'more" as Popeye used to say.

I've pushed 550 HP at 427 inches around the streets and track-for a long time. Since '03 when I installed Shelby heads, it's run 11's at the track, had 4 valve adjustments (.600"+ SFT cam) and no broken parts. Goes to 6800 when I feel like it and I've had to change a clutch disc in '09. Since the previous disc in '95. Considering the performance, I'd say that it's reliable. You decide.

Brent, why are you fencing with our nerd in the shop class?
Time for some 'Mythbusting' and I'm here to help.

Patrick, or would you prefer Mr. T? You're a very intelligent and resourceful guy. But your real talent is manipulation. You know:
A. If you repeat fallacies often enough to a less discerning audience, they will become 'fact'.
B. Spouting posts and threads from the net without your own experience and brow-beating others to support your stance is BS.
C. Rod's 600 is STILL a lot more than your 450-pipes, pumps or an 800 pound gorilla in his car not withstanding.
To wit:
I watched 3 DTS dynos run 3 engines a day. Dynos were calibrated annually by DTS. Those engines had no (mechanical) fuel pumps, water pumps or alts. On rare customer requests we ran a water pump or alt. The back to back loss of a water pump was 5 to 8HP at power peak. An alt. was 2 to 4. Dunno for sure but I don't think a fuel pump is more than 3 or so HP. All the dyno headers were very efficient and went into 2 large corrugated tubes which went out of the building and into a pair of Flowmasters. Like you, here's a little support from Stewart if I have no credibility:
http://www.stewartcomponents.com/tech_tips

See that at 150GPM, the HP consumed is 8.8 for a SBC.

My own Cobra experience is more telling. Firstly, you can thank me for your Stainless Specialties pipes. In 1989, I called Lou and asked for a set of Cobra stainless sidepipes.
He said; 'What's a Cobra?' and ' Show me what it looks like and I'll make 'em for you'. So I sent one mild steel ERA pipe to NC and Lou suggested I came down for a talk. I did, we did and the deal was I buy the doming die and I get the prototype set of pipes to have and to--test. Having them fit perfectly and look beautiful, I put Lou in touch with Peter and the rest is history as they say.

But I was aware that sidepipes eat HP and in a year or so I told Lou I wanted to find more. He too realized that the original 2" core was hurting so he whipped up a new set with a 2.75" core. But I told him to cut and flange the collector for a small turnout for the track-true open headers. He said fine provided I chassis dynoed a comparison. And now on to that:

When first machined and built my 427 made a best of 530 with non-ported iron med. risers, my then OE water pump and Hooker 1.75" dyno headers (too small by .250") Also had stock iron (1.73) rockers.
In '03, I bought and installed Shelby Stage II's and Sharp roller rockers and stands. I've maintained that they added 20HP to the combination. And then I went to Matt Grillo's chassis dyno which Mike Ashley's Pro Mod had pegged at 2000HP the week before.
First tests were the early sidepipes, then the new version and then the open headers.
First set: 402WHP
New set: 457WHP
Open headers: 462WHP
The amazing thing is not the 55HP gain over the first design, but rather that the second design was only 5HP away from open headers. And of course all the primaries are 2" pipe unlike the build dyno tests.

So, as I questioned Sharapa in his dyno thread, the parasitic losses are no where near 26% as you're preaching to Rod and less than the 22% he and his friends have seen.
My numbers work out to 17.5 to 18.5% consistently. And the local IRS Cobras I've seen are comparable. A live axle car may be less-the big transmission gears in Richmonds and TKOs can add to loss -so we can only generalize.

So please stop perpetrating myths-it doesn't help make other guys smarter or understand things better. And quit harassing Lykins-he's done a thousand builds and tests. He's trying to make a buck and share his time and experience. And don't get all kissey-face with him either.

Uhhh, ok then... "thank you" for my pipes, and if I want kiss Lykins, that's my own business.%/