OK, I'm considering headers for my slant six, perhaps bolt on solution from Clifford or Aussiespeed. BUT, I'm intrigued by Dutra Duals! Which is best?

Also, completely unrelated, are '66 and '67 dart reverse lights the same?

thanks all,

First hit from a quick search

This topic comes up quite a bit.

Dutra Duals allow you to keep carb heat.

Dual Dutra Duals do not.

Headers do not.

This would be a deciding factor. If you daily drive the car, startup driveability is better with the Dutra Duals.

Once the intake has heat soaked, not much difference.

Headers will deliver highest power for a given build. Generally this will equate to better E.T. at the strip. How you drive will determine if this will be noticeable on the street.
The sound is different, so depending on how your butt dyno is calibrated, headers may seem faster. Or not.

CJ

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Part of Tyrde-Browne Racing

i have duel duels they aare heavy cast...not going to rust away.....figger they will proably be on several engines....instead of several sets of header on one engine

Be very careful before you decide to spend any money with Clifford. They have a long and ugly reputation for being a bunch of clowns; see for example here, here, here, here, and here. Much of what they sell is inaccurately described, and a lot of it is not even slightly cost-effective. Even though some of their stuff is fine, spending money with Clifford means spending money with an individual who is happy to sponge off the slant-6 community and take our money in exchange for wrong parts and endless runaround.

Dutra Duals are an excellent pick for upgrading a street-driven car (you get to keep the automatic choke and the intake manifold heat, which is important for reasons having nothing to do with the weather where you live), bring no hassles with leaks, fit, or rust, and buying them means supporting a very active contributing member of the slant-6 community.

Your choice.

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

My recommendation would be to go with the "Dutra Duals".

I have retained the stock rear half of the manifold, and am running the Dutra front casting. Performance from that modification alone made me happy. The sound is MUCH different as well from the stock system, even with a straight pipe on the single exhaust (All that makes me think of are those guys running around in Cummins equipped Dodges with straight pipes... yuck)

As others have said, if you drive it everyday, the front Dutra casting with the stock rear half of the manifold would be your best bet. Guess what else? The Dutra manifold will LAST. I've had mine for years, and it looks just as good today as it did when I picked it up from the man himself.

~THOR~

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1984 D100 Shorty Custom
Certified Auto Appraiser - RevItUp Classic Appraisals
President - Cherry City Bombers CC
Part of Tyrde-Browne Racing

"...a very active contributing member of the slant-6 community"

I believe that might qualify as "an under-statement"...

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obliquely-inclined state of mind

Hi All,

Thank you for the quick and thorough response. This is truly a wonderful community, and I'm happy to support it (besides my token Christmas gift at the end of the year). I grew up building engines (mopar and, ugh, chevy and ford) and drag racing (street and strip) with my five older brothers. I was partial to the mopars, not just the engines, but the whole philosophy (at least as I perceived it) of their products. Of course, mopar big and small block V8’s have their wonderful qualities (that 440 six pack has impressive torque off the line), but the slant six is bullet proof, and I love it.

Yes, I have seen rusted headers and especially have dealt with leaky headers. My dart is my daily driver (can you think of a better commute car than a slant-powered one?), so I do want the advantage of using the heat for the automatic choke, etc. I’m not going to race this car, but I’m not satisfied with the cold performance issues or the stock intake manifold and one-barrel carb. Once my car is warmed up it performs fine, but is of course, weak. It’s as if the slant six were specifically designed for upgrades.

So, I believe I will go with Dutra Duals. Thanks for steering me away from Clifford!

I have to consider my intake manifold upgrade. I really like the idea of an Offenhauser with two singles, but I’m wondering if those two singles are hard to match/tune. It seems like the fuel distribution would be optimal with such a setup, but let me know if anyone has experience with this intake. I don’t think I need two two barrels or a four barrel, I think that is overkill for my purposes. One of my brothers had a slant with a four barrel, and it sure ran great, but the gas mileage suffered. I just want to balance an increase in power with some semblance of gas mileage.

One last question, does anyone run the Dutra Duals with dual exhaust pipes? If so, do you use a crossover to mix the flows or run all the way back individually? I’ve never heard a slant six with duals, must be pretty neat….

thanks again.

'67 Dart 270

Sounds like you are definitely at home here!

Excellent choice!
A nice (read: In good repair) 2 barrel such as a Carter BBD, or a Holley 2300 (My favorite) work great. The Holley when tuned properly will return excellent fuel economy, and very acceptable driveability/power.

Be aware that the whole intention of using the Dutra Duals is to maintain manifold heat from the exhaust. You go sticking a dual carb intake on there, and you won't be able to use it. It needs to be a single carb to utilize the manifold heat junction.
Are you kidding me?

We have a racing team name on the West coast here called "Killer Bees"... you set up a slant with dual exhaust, and regardless of whether you pipe them back together or not, it sounds like a swarm of killer bees going down the strip!

To get all drool-y, go on youtube and type in "Slant Six"... once you've weeded through all the stupid "Slant six games" videos, you will find many many videos of cars in various stages of tune, with all different types of exhaust. You will know when you find one that has duals.. trust me.

~THOR~

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1984 D100 Shorty Custom
Certified Auto Appraiser - RevItUp Classic Appraisals
President - Cherry City Bombers CC
Part of Tyrde-Browne Racing

Years ago (mid 80's) I ran Clifford (when Jack Clifford himself was running the business) long tube headers and 4 barrel with true duals out to the rear on my 65 Dart convertible. Sounded like a V8 with duals at idle. On the gas sounded totally different.

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65 Dart station wagon slant 6 - now under construction
47 Dodge Custom 4 Door sedan
87 D100 Short Bed slant 6

Retired USAF 1966-1986
Retired US Postal Service 2004-2014

On a street vehicle... you want to run a "cross-over" tube. (balance pipe)
The "balance tube" helps cut down on harmonics from the exhaust system and also helps mid-range torque.
DD

OK, thanks so much everyone.

Doesn't the pro line dual two (offenhauser dual single) utilize the heat riser from the back 3 manifold section?

Yes, the Offy dual manifold does have a manifold heat provision.
DD

I have the Hooker headers with the heat riser pipe. M-1 2bbl intake. The headers are probably $500 new. I got mine used. I do have duals with a H pipe.

I have a drone with the Superior round turbo mufflers until I hit 70 then you can't hear the exhaust inside.

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'72 Duster 198 stock cam, 3:23's Hookers on jack stands for 8 years in the driveway
'79 Maxivan 360 Offy Qjet Comp RV cam/rusting in the driveway.
93 D350 160HP Cummins Auto Dually Clubcab needs a injector pump
2005 Golden Couch Buick

I now have my Dutra front manifold and am reading on this thread about an H pipe. I'm wondering just where would be the best place to install the H. Is there some formula for how far the H is from the exhaust manifolds?

I don't even have my Dart yet and I've been building parts for it. Next week a truck will deliver my '66 GT hardtop to me. I'm about to have a kitten just waiting.

Jerry in Denver

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Jerry in beautiful Colorado

Faster than the speed of sound!!!

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MRO....

Cheap, Fast, Reliable.... Pick 2...