Original duel 4 intake information

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hey guys/girls
I purchased a original duel for intake manifold for my poly 318. I have been having issues finding information on what carburetors I should have on it. My engine is bored out .030 and I had a cam ground down to brown spec in the engine. I’ve found some information on them but haven’t really been able to find a cfm raiting on them. Was thinking about getting a couple of 390 holleys then jetting them down to like 350 and building up from there to find a good balance.
 
Iz your intake set for those 2X4 BBL Carbz setting North and South? If so I'd go with Edlebrock carbs. their close to exact copies of the Carter AVS's that mother used and just jet AND needle 'um down to 300-350 or maybe 400. You'll have $500 - $600 in the carbs and fuel lines and carb kit but mother waz still using the AVS's after she dropped the WCFB's and the AFB's 'cept for ah short side step in the 70's for???? Brain Lock, Hellup?
 
You can buy reman. Edelbrock 500 cfm carbs from Summit for abt $330 each with electric choke. The dual quad fuel line and linkages are also available. Pretty much plug and play.
 
This guy was using Eddys, don't know what CFM. This motor was cool - was in a '65-6 Plymouth.
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hey guys/girls
I purchased a original duel for intake manifold for my poly 318. I have been having issues finding information on what carburetors I should have on it. My engine is bored out .030 and I had a cam ground down to brown spec in the engine. I’ve found some information on them but haven’t really been able to find a cfm raiting on them. Was thinking about getting a couple of 390 holleys then jetting them down to like 350 and building up from there to find a good balance.

Those carbs were Carter WCFB's, Probably 1632S model if my memory is still working. They were about 300 CFM each and even at that they tended to drown the engine in fuel unless a progressive linkage was used. What you can get away with will depend a lot on what cam and what type of headers you decide to run.

Dave
 
No headers on my car just stock exhaust manifolds with 2 1/4” out to the back. Was told there wasn’t really an option for headers unless I made my own for my fury.
 
Sounds like a fun project - just make sure you pay attention to what is suggested about the brand, CFM, linkage setup etc, as this can be a great setup or a dog that won't run right.

318 poly motors are excellent, so it should be able to be a fun setup.
 
Ya I almost swapped it out for a 383 but cause it is the original stamped block for the car I kept it instead. But it is a little more challenging to get parts for as most people have no idea what a poly is.
 
Eight barrels on a 318 with stock manifolds? I'm no pro, but if you're taking in that much air, you gotta be able to rid of it just as effectively as you're taking it in? Again, no professional here, just my thoughts, any others opinions welcome.
 
The Poly 318 2x4bbls would have been stock on the '56 Fury models, which would top speed right with a Chrysler 300B, possibly even a mph or two above . . . on the sands of Daytona Beach back then. Accounts of that in www.allpar.com. Full production specs for back then.

Not sure what "brown specs" are for the reground cam. The Carter WCFBs probably flowed about 400-450cfm at best, so the larger carbs could well over-carburet the engine, even with a more open exhaust system.

An interesting project!
CBODY67
 
to make a 2x4 setup really roll you must remember these carbs were setup for one carb per engine.. my car ran 14:90 with a 2x4 setup with carter afbs... ran 13.00's with single 4bbl.. so big issue.. i found that by lightening [grinding down or cutting chunks off] the counterweighted air doors in the secondaries the car was much faster..i found some junk afb's and took their counterweighted doors.. modified the air doors by cutting [had progressive linkage] so rear carb i took 50% of the weight off and front carb 75%..car ran 13:10...so if your 2x4 setup isn;t performing modify the carbs... its so easy a caveman could do it..
 
In an old "Hot Rod Magazine" annual publication, circa 1962, the counterweight weight/shape was mentioned as a way to get things to open quicker, but the irreversibility of the situation was also duly noted. Have to do it slowly and methodically, rather than otherwise. That was back when the Carter AFB was the premier performance carb. Key thing is that once the counterweights are lightened for a specific motor, the carb can become more application-specific than before.

A progressive linkage was also a necessity. Letting the front carb do the idling and lower speed work, then kick-in the rear carb for higher rpms.

Wondering if one of the reasons that a 2x4bbl engine typically sounded more radical than a similar 1x4bbl had to do with the mixture distribution dynamics of the intake manifold?

CBODY67
 
Wow thanks guys all this information is a big help. The brown spec I referred to for my cam is racer Brown Mopar profile that I got from direct connection performance manual. It’s not to aggressive but gives it a decent lump when idling.
For the carbs on the manifold your suggesting that I have the front carb set for the idle and have the rear one closed off. I was going to use progressive linkage as I was concerned about the engine flooding. Still a bit of a concern while I drive in the city especially with all the traffic lights where I live.
 
I believe that on a 2x4bbl set-up, the two carbs need to be matched rather than just two of the same number. Some internal differences which might not work (for a normal 4bbl) when being used on a 2x4 set-up. Like the position of the idle fuel holes in the venturi and how far open the primary throttle plates are at the resultant base idle.

In the '50s, multi-carbs were the way to get more air into the cylinders. The base/normal carbs were very small, cfm wise, compared to the carbs of the middle '60s. Back then, carbs were rated in "square inches of venturi area. The factory B/RB 2x4 and 3x2 setups happened due to this. As carbs and intake manifold design knowledge improved, with larger carbs, then a 1x4bbl could make the same or more power than the prior multi-carb set-ups. Just as one of the later 426 HEMI 1x4bbl intakes and appropriate carb makes more power than the prior 2x4 factory set-up. Less complication with more power . . . not a bad deal.

But where historically correct is operative, you deal with that situation too. Hopefully with a little newer set of Carters. I'm not sure if the latest AFB2 will match the mounting pads on your intake or if they go small enough, but that might be a good upgrade, adjustable secondary air valve spring and all. IF they'll directly bolt-up and be about 500cfm, which is KEY to them working, to me.

Racer Brown is an old-line Mopar-oriented brand of cams they used back in the later '60s. Do you have an Poly "A" motor or an "LA" 318? Reason I ask is that I don't recall any DC stuff for Poly "A" 318s, only the "LA" 318s. Did I miss something?

Just some thoughts,
CBODY67
 
My engine is an A block, there are parts from LA small block 318’s that swap over. I’ve done reading and have found lists of parts from 318, 340 and 360’s that can interchange to help out the poly create more power.
 
to make a 2x4 setup really roll you must remember these carbs were setup for one carb per engine.. my car ran 14:90 with a 2x4 setup with carter afbs... ran 13.00's with single 4bbl.. so big issue.. i found that by lightening [grinding down or cutting chunks off] the counterweighted air doors in the secondaries the car was much faster..i found some junk afb's and took their counterweighted doors.. modified the air doors by cutting [had progressive linkage] so rear carb i took 50% of the weight off and front carb 75%..car ran 13:10...so if your 2x4 setup isn;t performing modify the carbs... its so easy a caveman could do it..

So the car was faster with a single four barrel than with the modified 2x4's? Was that with a 318? Dual carb set ups are cool, but I have a hard enough time getting one set right. Not to discourage you Canadian 66 Fury, sounds like you already have what I would assume is a rare manifold. Best of luck with the endeavor!
 
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