Are Dutra Duals a set of headers, or just a manifold?

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'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me

Dutra Duals are cast iron dual exhaust manifolds for the Slant 6
DD

So they're just normal manifolds? How are they so popular? Just because they have dual collectors?

(I am not in the know)

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'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me

No, they're not normal manifolds. The front is a custom casting by Dutra. The back one can be a modified stock manifold that retains the choke stove mount and carb exhaust heat provisions, or you can opt to mount a second custom casting on the back half if you don't plan any cold weather driving. The entire point is to open up the exhaust system, which is usually the biggest restriction to overcome when "rodding" a slant engine.

An added benefit is that they're cast iron, so underhood heat is less and fit is better than headers, plus, you'll be able to pass them on to your heirs.

Roger

Think about the SL6 firing order,
1 - 5 - 3 - 6 - 2 - 4

With the "3 & 3" grouping, like the D. Duals, there is twice as much separation time between pulses, this really helps reduce back pressure.
DD

I'm interested in Dutra Duals for my '64 (225, 904), but I'm concerned about exhaust routing the second pipe past the 904 cables, kickdown, and cooling lines. It eyeballs kind of tight. Anyone tried this? Got pics?
Being an optimist, I've already cut the front off the exhaust manifold that came with my Super Six setup, and am trying to square it up enough to seal.

That is, I'm prepping the rear portion to seal. Anyone have a good use for cut-off front branches?

I'm looking for ways to increase the gas milage and power of my street 63 Dart 270. I'm planning on doing the super six upgrade and am looking into dual exaust. What kind of improvement in these regards could I expect from a dual system in general and Dutra Duals specifically.

Keep in mind that I would like to keep from sounding like a Harley on the freeway. Do I lose the benifits of opening things up if I then constrict it again with sound dampening devices?

Thanks,

Nick

Sounds good to me. What's the expected asking price if/when the /6 forum gurus produce 'em?
http://www.slantsix.org/forum/viewtopic ... 9947#19947

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'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me

You can get 3 to 6% increase from D.Duals, take it in power or in MPG, most tend to use the increase in power and throttle response.

You can keep the system quiet and have improved performance, the trick is to keep the pipe large (2 inch or more) and use a large reverse flow muffler. I also use a resonator to cancel even more noise.

As for pipe routing, it is tight but it can (and has) been done. I have installed the dual pipes through the bell crank on manual shift cars and it clears, auto trans cars have even more room to work with.
DD