Thanks Doc, that helps!

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66 Lil' Red Piggie Valiant (Mater Crusher) - Thanks Zilla!!!!! 72 Demon (Number 1 Son's)

Absolutely does!

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1969-1/2 Dodge Super Bee A12 (440 Six Pack, 4-spd, Dana 60)
1974 Plymouth Duster 360 (4-spd, 8.75")
1973 Plymouth Duster (225, auto, 8.25")
2001 Dodge Ram 1500 QC 2wd (5.9L, auto, Dana 60)

these are really scientific explanations, thank you for such a detailed and true info. Doc, did you ever tested your manifolds on the dyno? How much extra power do they make?

Thanks, Doc! Those are some great exhaust tips. (Pun unintended) I'll keep this in mind when I go to replace my manifold.

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Chuck and the Flying Valiant

I have never done any dyno runs but I have done some dragstrip work where I ran a car with a stock set-up and then changed to a D.Duals system... I picked-up a little over 12% improvement with that car and test.
DD

the question I have for Doc is when are you going to make long tube dutra's? Something a few inchs longer and with that taper you spoke of? that would be sick. Works for front and rear location for exact same flow characteristics. Wow really sick!

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it's like a vw, sounds like a million miles an hour but goes really slow. (for now)

I wish I would have seen that photo before I took my car in for a wye pipe. The guy made a wye pipe for me okay. But the two lengths are far from being the same. He dumped the pipe under the right manifold right into they wye. I am lucky if there is 6 inches there, compared to the much longer pipe coming from the front manifold. How much is that going to make a difference? But realistically speaking. I was lucky to get this wye pipe built. It took him about 4 hours to complete it.

As first noted, most of the gain from doing a "3 & 3" split is from increased pulse separation time.
Getting the primary pipes the "right" and the same length is more important with power band tuning and scavenging... where you want to carefully time when and where a high pressure pulse wave enters the collector area.

As for making a new exhaust manifold casting for the SL6, I did a design a while back that does have longer runners and it is a "tri-Y" configuration. Here is the cool part... it keeps intake manifold heating and has a large outlet flange that comes out sideways, just right for mounting a turbo.
It is a big, heavy manifold that has a lot of metal content in the center. I am concerned about casting problems (shrink and twist) as well as cracking problems when used in Turbos applications.
DD

Doc, could the stock hyper pak exhaust be used as a model to make a longer cast iron header? Thanks, Wayne.

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66 Lil' Red Piggie Valiant (Mater Crusher) - Thanks Zilla!!!!! 72 Demon (Number 1 Son's)

Good idea........Doc do you have a set of these to use for patterns????

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

I doubt it. The exhaust manifold has to make a turn down almost immediately to avoid running into the intake manifold.

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Casually looking for a Clifford hyperpak intake for cheap.

There already exists a really nice "long sweep" front-3 exhaust manifold. Plans are underway to reproduce it. It won't be soon, but it probably will happen.

The rear-3 item presents fit challenges; remember the Hyper-Pak item barely clears the '60-'61 direct-drive starter (and only if that starter is modified), and will not clear any gear-reduction starter — neither the Chrysler- nor the Nippondenso-made unit.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

If nothing else, you don't have to worry about your exhaust manifold cracking if you have Dutra Duals.

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"Ja, Ich fahre ein altes auto."
'78 Volare 225
'67 Charger 318

Does anyone know if this front exhaust manifold will clear accessories like A/C pump/brackets and P/S pump?

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Casually looking for a Clifford hyperpak intake for cheap.

Do we have pictures of this manifold Dan? Or is it top secret, I'll have to kill you kind of stuff.
Thanks, Rick