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PostPosted: Thu Sep 26, 2019 11:49 pm 
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Joined: Sun Sep 22, 2019 10:46 pm
Posts: 3
Car Model*: 1967 VC Valiant
I have a 1967 Aussie built VC Valiant in Wellington, New Zealand. It's an Aussie stock 225 slant 6 with a 2bbl Carter Carb, original exhaust system (it's a 2 inch pipe at present) and manifolds. I use it as a road trip vehicle around NZ mostly and ordinary street driving when I'm in NZ when I'm there (I currently live in Sydney).

I've been thinking of doing the intake manifold / exhaust system for awhile to give it a bit more noise, fuel economy and HP and to cure very minor exhaust leaks. The VC is fairly silent at idle as it is but would be cool for it to sound more throaty at idle/low cruise speed, without too much of a rasp at 60-80 mph (although I tend to have pretty loud music up when driving long distance). I was intending on going for Dutra Duals, maybe to a Y connector to a single 2.25 or 2.5 inch pipe out through maybe a flowmaster muffler or something similar but have no firm views and welcome suggestions.

As for the Dutras I'm aware that it's possible to go for dual Dutra Duals or only the front Dutra, but if only going for the front, that would require a cut/weld job on the rear exhaust manifold cylinders to retain the heat riser, which may be a challenge. In New Zealand in the winter it's not really that cold in most places and it's rare in the North Island for it to be too much below zero at night in the winter. I wondered if people had insight on the effect of dual Dutra duals verus a single dutra on the front and the original manifold on the rear on a 225 Slant with a 2bbl Carter Carb, in driving conditions where the ambient outside temperature is likely to be mostly between 5 and 30 degrees Centigrade.

I'd like to be able to essentially take the parts, say an AussieSpeed front and rear dutra dual, plus a short runner 2bbl intake manifold, plus gaskets, once purchased, to a good workshop in NZ ready to strip the manifolds and bolt on, plus do the exhaust pipe work to get it done all at once.

What do you think are my best options and why?



Cheers
Mark Robertson


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PostPosted: Fri Sep 27, 2019 2:18 am 
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Welcome to the site, Mark!

This sounds like a nice project. Some will tell you that the carb heat from the rear modified stock manifold is highly desirable. Since this is an occasional use vehicle and you are having someone else do the work, my feeling is manifold heat is not so important as ease of fabrication and certainty of building a reliable system without tons of input from you. If it were me, I would go with the Dutra Dual manifolds front and rear and have them build a Y-pipe (primary pipes) that uses 2" diameter tubing. Get a Flowmaster or Magnaflow or similar Y-junction pipe and then run 2.5" single from near the transmission X-member out to the back of the car. I like the Jones exhaust quiet flow mufflers, which make a little noise but are still not too loud. You will need a mini starter to clear the rear Dutra manifold, most likely.

Since you already have a factory 2bbl on a factory manifold, you will not gain much by going to an aftermarket manifold and carb on a stock engine. You might want to increase the jet size on the carb after the exhaust switch. Get the exhaust shop to weld a bung into one of the head pipes about 18" beyond the Dutra manifold exit so you can run an air-fuel meter for carb tuning, should you want to do that now or later. You can always plug the bung for now.

Well, that's some initial thoughts. I/we can provide further input of course!

BTW, Christine and I spent a wonderful 5 months in Wellington, NZ in 2005. Really thought about moving there... EnZed is amazing.

Lou

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"You mean you still have a Slant 6 in that thing?"


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PostPosted: Fri Sep 27, 2019 3:35 pm 
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Joined: Sun Sep 22, 2019 10:46 pm
Posts: 3
Car Model*: 1967 VC Valiant
Attachment:
File comment: My VC in fron of the old Bank of New Zealand, Raetihi
50748201_10156707537435767_6603555966136877056_n.jpg
50748201_10156707537435767_6603555966136877056_n.jpg [ 62.54 KiB | Viewed 538 times ]
Dart270 wrote:
Welcome to the site, Mark!

This sounds like a nice project. Some will tell you that the carb heat from the rear modified stock manifold is highly desirable. Since this is an occasional use vehicle and you are having someone else do the work, my feeling is manifold heat is not so important as ease of fabrication and certainty of building a reliable system without tons of input from you. If it were me, I would go with the Dutra Dual manifolds front and rear and have them build a Y-pipe (primary pipes) that uses 2" diameter tubing. Get a Flowmaster or Magnaflow or similar Y-junction pipe and then run 2.5" single from near the transmission X-member out to the back of the car. I like the Jones exhaust quiet flow mufflers, which make a little noise but are still not too loud. You will need a mini starter to clear the rear Dutra manifold, most likely.

Since you already have a factory 2bbl on a factory manifold, you will not gain much by going to an aftermarket manifold and carb on a stock engine. You might want to increase the jet size on the carb after the exhaust switch. Get the exhaust shop to weld a bung into one of the head pipes about 18" beyond the Dutra manifold exit so you can run an air-fuel meter for carb tuning, should you want to do that now or later. You can always plug the bung for now.

Well, that's some initial thoughts. I/we can provide further input of course!

BTW, Christine and I spent a wonderful 5 months in Wellington, NZ in 2005. Really thought about moving there... EnZed is amazing.

Lou


Many thanks for your helpful comments Lou.

Yes I enjoy Wellington too and was out fishing there last week actually.

I'll go for dual dutras and see how I go. I note that AussieSpeed here in Australia has now modified the rear Dutra to avoid the starter motor issue. See http://www.aussiespeedshop.com/product/ ... 0567-pair/ - I just ordered a set.

Kind regards
Mark


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PostPosted: Fri Sep 27, 2019 5:19 pm 
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1 BBL (New)

Joined: Sun Sep 22, 2019 10:46 pm
Posts: 3
Car Model*: 1967 VC Valiant
Just thought I might add for general info, my 67 VC Valiant with the original 2bbl bbd Carter setup has no trouble crusing at 80mph and will do 100mph. Gas wise, my guesstimate is it uses about 10 litres per 100km.


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PostPosted: Wed Oct 16, 2019 1:48 pm 
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Joined: Sat Nov 27, 2004 8:03 pm
Posts: 5140
Location: IRWIN PA
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Nz has a pretty cool car culture from what I have seen.

Welcome to the site.

Sometimes in a warmer climate the carb heat is not as crucial. On my stock 1bbl 64 dart all of the carb heat boils and vaporizes the fuel on hot days.
I have to park the car outside for an hour or 2 so my house dosent smell like gas.. fyi.

Also Lou recommended I watch the worlds fastest Indian movie which features NZ and the main character in it is From Invercargill.

Cheers!

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Greg Ondayko
69 Dart http://www.youtube.com/hyperpack
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