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

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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Home of Slant6-powered fun machines

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

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. Gas wise, my guesstimate is it uses about 10 litres per 100km but probably a bit more.

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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http://www.youtube.com/hyperpack

Hi all,

So I've gone ahead and done the work outlined above.

My car is an Australian built 1967 VC Valiant. The engine casting no. is 330 4 29991 - which makes me think that the slant is a later model slant than 1967. The stamp behind no 1 looks like O 22 R 1980 E.

Originally it had 2 barrel BBD Carter Carburettor, manufactured by Email Ltd in Australia (which was an Australian company that made these under licence) and is a stock VC Valiant as they were built in South Australia. (photos attached for those interested)

Over the past week I've had the following installed by the boys at TMS Racing in Kapiti, near Wellington, NZ:

* An Aussiespeed Hurricane Long Runner intake manifold
* A brand new 07448 - Holley 2300 350 cfm carburettor (I originally wanted to keep the Carter BBD but for various reasons that did not happen)
* Dual Dutra Duals front and rear
* Remflex manifold gasket
* 2 inch pipe from the Dutra's to a Flowmaster 2 inch in 2.5 out Y connector scavenger pipe
* 2.5 inch straight out the back through a Flowmaster 50 Delta Flow.
* a set of 6x new spark plugs (NGK BPR5FS)

The slant fires fine, looks cool, sounds great, revs up ok but is missing on the no. 6 cylinder under throttle and at lower revs/idle. It's possible to drive through this and by 60 - 80 mph it seems fine unless you put your foot down too heavy. It's worst at about 40 mph. Our guess is either the points or perhaps a lash adjustment on No. 6. Also no six exhaust temp on the dutras is a lot cooler than the other five.

I'd be welcome for suggestions as to possible cause and fix.


Thanks for your help

Cheers
Mark.

These aren't calibrated out of the box for a 6 cylinder or even worse a long ram intake application... you'll need to tear it down and change the base jets to 58's,
change the acc pump cam to orange and see if that helps performance... performance would be better if the engine was 9:1 SCR with an RV cam and some port work...FYI.

It looks like you have the PCV valve hooked to the number six intake runner. That will make that (#6) cylinder run lean. Reroute the pcv to the connection on the carb, and plug the fitting on the manifold.
PS: I would be concerned about the fuel filter being tied to the intake. Might rub a hole in the plastic.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 225 nitrous
64 Valiant Signet
64 Valiant 4dr 170

Thanks guys.

We down jetted to 58s when had it on the dyno. I tightened up the no 6 exhaust valve lash a bit and that helped a lot. Running reasonably smoothly but bogs a bit at WOT and still a bit missy in the 40 - 50 mph range.

I didn't think about the PCV hose being in the a different place. I'll see if moving it makes any difference.

As for the fuel filter, that was very temporary. No idea why someone thought that was a good idea. Had that sorted straight away.

Cheers

Just following up on my post above. All issues ironed out now but there were a few along the way and this wasn't a cheap modification but I am pleased with the result.

The performance is much improved and a lot more horsepower, sounds great both at idle and when cruising. Wouldn't want to be much louder but the Flowmaster 50 Delta flow is a pretty nice balance for my purposes as it's not a daily driver (although it is the only car I own).

If you are interested in the before and after, and some nice road trip shots from New Zealand you can have a look at the YouTube video I made here https://youtu.be/teKt5Yj-mSM - This video is best with a set of headphones or a stereo with good bass speaks to get an idea of the real sound.

Thanks all for your input.

Keep on cruising.

enjoyed your article, thanks. I think it is likely that this is a later engine, as the VC was a 3 core plug engine, and yours has 5, so most likely a VE or VF engine. The VC were just a single barrel originally, so the 2 barrel either came with the different engine or has been upgraded at sometime.
If any readers are interested, these RHD VC Valiants were manufactured in Aussie, but were both assembled in aussie and CKD in NZ.
The NZ assembled one ended up with many items that were made in NZ, so there are small differences between the two. I suspect this car was aussie assembled and imported as the seats are different to the NZ ones that I’m familiar with.

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1967 VC Valiant

Thanks NZ Pete.

That confirms what I suspected. This VC was first registered in NZ in 1970 as far as I can tell. So yes, I think you are correct it is likely it was imported from Australia.

Cheers
Mark.