My '64 Valiant had headers w/ flat washers instead of cones on the ends of the exhaust manifolds. It came with a Clifford 4bbl intake, which I am keeping.

I have switched to Dutra Duals exhaust and keeping the Clifford 4bbl. I assume since the intake is aluminum, and the Dutras are extra thick, that the ability to expand and slide is not as important compared with the stock manifolds.

So are the washers still important?

Insights and expertise always appreciated.

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Joe Hoppe

71 D100 225 Super Six 727 AT on 2008 Crown Vic CopCar frame

64 Valiant Wagon 225 904 AT 3:23 8.75"

D

I haven't used a special washer (exc triangles) in 30 years. I use the green gasket from Brian Droschak and make it good and tight (20+ ft-lbs).

Lou

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Home of Slant6-powered fun machines since 1988

See post below

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Doo Ron Ron and the Duke of Earl are friends of mine.....
https://www.youtube.com/watch?v=uX8Nj8ABEI8

The special end nuts and conical washers and low tightening torque were there on the OE manifolds to allow for expansion of the thin cast iron OE exhaust manifold. We all know that cracked exhaust manifolds was a issue to some degree with slants from all years.
The Dutra exhaust manifolds have two features that make them much less likely to crack due to thermal expansion. They are a two piece design and they are also a much thicker iron casting. I tend to use the conical washers on the ends because I have them. I use regular nuts and tighten them more than the stock setting. I have never heard of a Dutra exhaust manifold that cracked or failed in use.
Because the Dutra’s are a two piece design, you need to take care to get the alignment the best it can be. The Dutra port opening are larger than the exhaust openings on a slant head, so there is some room to be off. What I did was align the manifolds to the head on the work bench- with the intake on - about as perfect as they can be. Then marked lines on the edges of the manifolds on the head with a Sharpie so I could repeat that set up when I mounted the manifolds on the installed engine. I also ground some socket clearance in to the Dutra’s to make the install easier.

_________________
Doo Ron Ron and the Duke of Earl are friends of mine.....
https://www.youtube.com/watch?v=uX8Nj8ABEI8

Thanks everybody for your thoughtful replies. I appreciate that there is a bit of differences in opinion. Once I get my engine running I'll see what happens.


Joe

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Joe Hoppe

71 D100 225 Super Six 727 AT on 2008 Crown Vic CopCar frame

64 Valiant Wagon 225 904 AT 3:23 8.75"

Me too. And I reuse the gaskets several times

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Lou Thanks for the tip, where does one buy these gaskets? is there a website? Thanks

Brian Droschak on this site. Can't remember his handle, but probably BrianD? Try a PM. Greg O also knows him and lives nearby.

Lou

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Home of Slant6-powered fun machines since 1988

Just Brian I think

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Does Brian have them made or is he selling off Cox Bros. gaskets?

I've been using one on my car since I put it together. Great gasket!

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Official Cookie and Mater Tormentor.

No he has a new guy making them for him.

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Awesome!

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Official Cookie and Mater Tormentor.