4bbl Carb questions

-
lgarbz

lgarbz

Well-Known Member
Joined
Apr 16, 2009
Messages
134
Reaction score
3
Location
Oregon
I want to put a 4bbl carburator on my 74 duster. It has a stock slant 6 and I wanted to know how to go about doing this, and if I need to do any mods to the intake before I can do this? Also what carb would you reccomend? Thanks.

Logan
 
You will need a four barrel intake. You'll also need to upgrade the exhaust to see full benefits. Probably look around for a used Offenhauser intake. A holley 390 or 450 vacuum secondary carburetor will work.
 
Unless you're going to port the head, add a hotter cam and run headers, a 4bbl is a waste of money in my opinion. A 2bbl would be a better fit on a stock engine.
 
cudamark said:
Unless you're going to port the head, add a hotter cam and run headers, a 4bbl is a waste of money in my opinion. A 2bbl would be a better fit on a stock engine.
Click to expand...

This is probably absolutely 100% right on the money. ......I was just answerin the OP's question 'stead of chunkin sumthin else at him. lol You forgot the biggest helpful mod for a four barrel, though. Raise the compression.
 
StrokerScamp said:
This is probably absolutely 100% right on the money. ......I was just answerin the OP's question 'stead of chunkin sumthin else at him. lol You forgot the biggest helpful mod for a four barrel, though. Raise the compression.
Click to expand...

Don't you have to shave the head to do that?
 
Cudamark-
Would a 2bbl holley fit on my slant without a lot of modification to the intake, or would I need to find a new intake as well?

Logan
 
lgarbz said:
Cudamark-
Would a 2bbl holley fit on my slant without a lot of modification to the intake, or would I need to find a new intake as well?

Logan
Click to expand...

You can find Super Six intake can be found in the classifieds here and at / 6 . org
 
And what carb would work well with a super six intake?

Logan
 
old tired rebel said:
Don't you have to shave the head to do that?
Click to expand...

No. You can do like I am doing and run the 198 rods with 2.2 Chrysler non turbo pistons and end up with like 9.7:1 without millin nuthin.
 
StrokerScamp said:
No. You can do like I am doing and run the 198 rods with 2.2 Chrysler non turbo pistons and end up with like 9.7:1 without millin nuthin.
Click to expand...

Ok where is a house cheap for rent near you???? :notworth:
 
i put a 465 vac holley on a cain 4bbl years ago on a stock 225 and a set of extractors and bigger exhaust with 3.23 gears standard on aus valiants really woke the old girl up went as hard as a 273 , obviously with a decent cam and more compression would have gone better but it really surprised me :wink:
 
So I'm thinking a super six manifold and exhaust with a holley 2 bbl 2300, sound good?

Logan
 
Sounds like a reasonable plan to me. You will need to make arrangements for a kickdown linkage for the 2300. Don't know if the Super Six linkage will work with the 2300, it was designed around a Carter BBD. Both Lokar and Bouchillon Performance make a universal kickdown for the Mopar A/T. Lokar is sold through Summit and others, Bouchillon has it's own site.
 
I understand the 2-barrel "Super Six" manifolds were common in later years like the Aspen and Volares, but not cheap. There are 4-barrel to 2-barrel aluminum adapters that probably fit (~$10 used), but then you may need a low carb for hood clearance. A 4-barrel aluminum manifold is better, but expensive. If you go 4-barrel, get the smallest possible, say 350 cfm. In theory, you can get better mileage with a 4-barrel than a 2-barrel, especially if small primaries ("spread-bore") and vacuum secondaries. Look at the Holley Economaster.

Longer term, consider changing to throttle-body injection. I recall some have adapted them to Slants. You probably need a custom adapter plate. Harder is the controller, like Megasquirt. The Holley Projection is easier, but 670 cfm is big for a Slant. Much Slant Six info on FABO, also www.slantsix.org.
 
2 Darts,
Is there a 2 bbl carb you can recommend me that I wont have to change the linkage?

Logan
 
The Super Six carb is the Carter BBD-81375. You can use this with the Super Six kickdown linkage with no alteration.

Mopar used to make an aluminum manifold, P4529115. I don't know if it's still in the system. It will work with either a Holley 2300 or the Carter BBD.

I echo BillGrissom's, and others, suggestion of looking over at SlantSix.Org. Lots of good stuff.
 
I personally prefer the carter BBD carbs because I think they get better mileage than the holleys and they are much easier to tune. The BBD is easy to find on two barrel small block engines of the era. it is outwardly the same as the one off the \6 it is just tuned a little different.
 
I saw once where a guy took a stock one barrel /6 intake took and a holley 350 cfm two barrel gasket to the machine shop and had the manifold machined to mount the carb.
It worked extremely well.
 
imo the best value= performance would be a carter 2 barrell that came on a 318 ....easy to tune /rebuild . check online at mopar specific wreaking yards for a aspen /volare 2 barrell manifold .....and replace all manifold bolts . and surface the manifold flanges for squareness and use premium gaskets. as a side note plug whats not needed and install a manual choke ,the thermo /auto electric choke will give you trouble at some point .
 
dustoff440 said:
I saw once where a guy took a stock one barrel /6 intake took and a holley 350 cfm two barrel gasket to the machine shop and had the manifold machined to mount the carb.
It worked extremely well.
Click to expand...

and you can have them mount the flange in the right direction...
 
I just got in a 2bbl Carter setup if you're looking to go that way. It didn't come with an air cleaner but I think I have something that will work. Let me know if interested and I'll post a photo.
Thanks, Mark
 
You must log in or register to reply here.
-

Back
Top