I currently have a Carter BBD on my 70 Valiant. I'm having problems making it idle smoothly and it doesn't get the mileage I expected. It also does not have the increased punch I thought it would have over the original Holley 1 barrel. I'm a diesel mechanic with very little carburetor experience. I've already swapped one BBD that had a pretty big vacuum leak around the throttle shaft. Is there a late model 2 barrel that will bolt up to the Super 6? What carbs should I stay away from? My daughter is going off to college this year and this is her car. I need to have this thing right before the fall. Any suggestions?

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70 Valiant Super Six

Put a properly set-up BBD on it. When they're all in order, they idle smoothly, run strongly and get good mileage.

I agree with Dan on the BBD.
I purchased a rebuilt one (oddly enough rebuilt by Holley)at Kragen auto for around $110.00.The BBD was off of a 70 318 car.It bolted right on with just the basic adjusting,and runs perfect.

Some say get a slant 6 BBD,others are happy with the 318 BBD.That decission is up to you.Like I said I am very happy with the 318 BBD.

Hopefully others will chime in on the /6 BBD vs the 318 BBD,and what would be your best choice.

Hope this helps

JZ

The 1970 cam is not known for having a good idle. Mine idles at around 550-600 and the car has that slight tremble. One of the reasons MOPAR went to the export cam in 71 was because of the rough idle quality of the earlier cam.
P.S. I vote for the 318 BBD

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Errr...No. Just 'cause your car doesn't idle properly doesn't mean that the '65-'70 cam is "not known for having a good idle". I've run several slant-6s with that cam that idled very smoothly indeed. It has 16° of overlap vs. the '71-'80 cam's 26° of overlap, so it's actually easier to get a smooth, low idle with the '65-'70 cam. I'm sure your idle will smooth out once you find and fix the problem (worn cam lobe or whatever).

well dan living in toronto you would not know how the cam in my car operates because the export(including Canada) dont have the same cam. in 1971 the export cam became the stock domestic cam.

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What year 318 BBD or /6 BBD should I look for? Do they have an electric or mechanical choke?

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70 Valiant Super Six

What year 318 BBD or /6 BBD should I look for? Do they have an electric or mechanical choke?

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70 Valiant Super Six

I believe none of the MOPAR BBD's came with an electric choke. you need to look for a Jeep model for that.
Any one will work as long as the throttle shaft dosen't leak. Ive used one from a 67 pick up, to an 80 aspen, I even grabbed one off of a Charger not sure of the year 73-74.

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You're right that I don't know how your cam in your car operates, except by your description of a rough idle symptom, but beyond that you're incorrect on a few counts here:

1) The Canadian market was not considered "Export", it was domestic. None of the export-spec slant-6s (e.g. '67-'75 2bbl) were sold in Canadian-market vehicles. The '65-'70 225s and '66-'70 170s in Canadian-market cars got the 1bbl carburetors and the same 240°/236°/16°/0.395" cam as the same-year, same-displacement cars in the US market.

2) What you are calling the "export cam" (the 244°/244°/26°/0.414" unit) wasn't used on the 1bbl export engines until '71; it was used on the 2bbl export engines starting in '68.

And even if that hadn't been the case,

3) I am an American who moved to Canada a few years ago. Most of the miles I've driven with the '65-'70 cams have been on US roads.

And what's more,

4) Your particular rough-idling engine still doesn't mean all engines with the '65-'70 cam idle roughly.

Depends on what you mean by "electric choke". The '73-up Mopar remote choke used an electric heater and control module, but was still a remote choke. And there are electric choke conversion kits for the '72 and older non-electric remote chokes.

The holley 2280 was used on 318 equip trucks. I believe the year could be around 1976.(I can check if interested) It is fully interchangable except for a minor modification to the choke linkage. The linkage modification is the same as the one required when using a 318 BBD as described in the super six article (I needed to modify the 318 BBD to get proper choke operation and mileage)

I won't say that the Holley 2280 is 'better', but I have had an easier time finding good working used ones. All the old BBD carbs I encountered had the leaky throttle shafts. I have other problems with my motor, so I can't really offer any mileage comparisions.

I can say that a NEW holley 2280 clearly beats a leaky old BBD for idle and mileage.

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1980 Aspen 225 super six

I never said my car idles rough. I said the car has a slight tremble when it idles at 550-600 rpm. who sets their idle that low? Those of us that want to give the illusion of a bumpy cam. I dont want my car to idle silky smooth. It will if I set the idle up 150 rpm where the book calls for. My car runs that good that I can set my idle that low. I actually READ that one of the reasons the export cam became the stock cam in 71 was to achieve a better idle quality.

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That's entirely possible. There's lots of incorrect info out there, just waiting to be read...including in the DC/MP engine tech books. Still doesn't mean the '65-'70 cam is "not known for good idle quality".

so just because you didn't read it first it isnt true?
get off of yourself

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