Help w/340 carb selection

-
Longgone

Longgone

John/68 Barracuda & Dart
Joined
Jul 12, 2005
Messages
6,896
Reaction score
81
Location
Newport News, Virginia
I`ve rebuilt my 68 340 w/AT to stock specs and rebuilt the original carb. I just cannot get this carb to do right, always loading up or hard to start when hot, not idling well, can anyone suggest a good Edelbrock carb that would be a candidate for direct replacement? Thanks
 
Eddy 650 or Holley 650 or 670 Street avenger. Vacuum secondary carb.

Holley's website has a tool in the upper right hand corner will help you select carb size & recommend part #'s. You can apply the results to an Eddy equivalent carb.

http://www.holley.com/
 
From what info I can find the stock carb Carter number (4425s)
flows 625 cfm. The Edelbrock 1405 or 1805 would bracket that with the 1405 flowing 600 cfm and the 1805 flowing 650 cfm. Now if I knew if the choke mechanism will connect to my existing set-up I could commit to something. As it is I`ll have to order the carb and won`t have the opportunity to see one first.
 
Long gone. The OE Carter is right about that 625 - 630 cfm area. So a typical performance bolt on was the larger 750 cfm from a HI-PO 383 or 440. The engine can use it well.

If your going to stay with the smaller carb, I would look into what was listed above. I would skip the AFB in favor of the AVS and a few more cfm's though.
Now if I knew if the choke mechanism will connect to my existing set-up
Click to expand...
The throttle bracket is a simple bolt on and lines everything up better than trying to tinker with the stock parts of the car and carb. They come in electric chokes. A simple 12v wire and your done. Grounf the e-choke to the houseing or carb itself.
No need for a manual choke cable or the OE bi-meatl spring in the well. The E-choke simply works better, No performance loss.
 
The main wells may be leaking on that factory avs. If you look at the bottom of the carb just outside of the primary bores you will see two soft plugs about an 1/8-3/16 in diameter. These plugs work loose. You can drill them out and install either 1/16 pipie plugs or set screws with locktight.

When these plugs become porous they allow fuel to be drawn into the intake causing a rich condition and hard starting after a hot soak.

Don't throw it away. Sell it on e-bay.

The eddy thunder series is a real close match.
 
My 340 is stock and I run the Edelbrock 650 AVS. I had to jet it up and put bigger accelerator pump nozzles on it to get the most out of it but it works really well. The Edelbrocks do tend to peculate fuel so make sure you get that special gasket from Edelbrock that goes between the carb and intake. And you don't need a choke, just pump the peddle, turn the key, and after 60 seconds of running it will be fine.
 
Ummm, didn't some of the high performance 383's get the 750? I thought so. I know the regular 383's had the smaller carb.
The 67-440 in my freinds Imperial had the small AFB.
 
go with the eddy. avs or afb style is up to you. the avs style you can tune the secondary door just like the original. get a calibration kit to change the jets and rods and DEFINITELY pop the airhorn off and reset the float level and drop. they are always off.
 
In an effort to keep it real, I`ve ordered a rebuilt factory Carter AVS through Holley that should be in Saturday. I`m keeping my fingers crossed.
 
rumblefish360 said:
Ummm, didn't some of the high performance 383's get the 750? I thought so. I know the regular 383's had the smaller carb.
The 67-440 in my freinds Imperial had the small AFB.
Click to expand...

'68-'70 383 hp had the same cfm carter avs carbs as the 340s had. I can't speak for the other years/models. Only the 440 got the bigger carb during those three years.
 
For some reason, I was thinking some of the hi-po 383's got the larger carb in some years. I know not all years, but, I do remember back in the day the older kids saying they got the 440 carb on top of there 383.

Ahhhhhh, old tricks never die.

How do you like the new Edel. AVS hy-bred?

Good luck Longone. Hopeit works out well for ya.
 
rumblefish360 said:
For some reason, I was thinking some of the hi-po 383's got the larger carb in some years. I know not all years, but, I do remember back in the day the older kids saying they got the 440 carb on top of there 383.
Click to expand...

I thought the 383 Magnums and Road Runner 383's had the bigger carb. too. Could've swore I read it in a Mopar mag somewhere a few yrs. ago. but mabe like other things, the memory ain't what it used to be.
 
Only the 440's got the bigger bore AVS's.

There is a good AVS article written by Richard Ehrenberg in Mopar Action in the '88 to '92 era.
 
Well John....you have frightened me into sending mine out to be done. It is a 68 also, but for a 4/spd(glad I don't have kickdown to worry about), and I want it to work like new. SOoo....thanks for that$$$

LOL
(hopefully,you will get yours right, and I can pick your brain, to gain some of your new-found knowledge)
 
MtNemoMopar said:
Well John....you have frightened me into sending mine out to be done. It is a 68 also, but for a 4/spd(glad I don't have kickdown to worry about), and I want it to work like new. SOoo....thanks for that$$$

LOL
(hopefully,you will get yours right, and I can pick your brain, to gain some of your new-found knowledge)
Click to expand...

You said it Bill, the magic words.......work like new! Yes, I bought the kit ,followed the factory service manual verbatim,:read2: and still this carb is disagreeable :thebirdm:????????? It`s gonna drive me to sniff glue. I shopped around for a place to rebuild it (most are out of business because of fuel injection) and when I did get quotes to rebuild it, they were in the $200.00 to $250.00 range plus the kit. For that money I opted to buy one from Holley`s remanufacturing service, just under 2 c-notes with a $35.00 core. I`m hoping this is the answer,and if it`s smooth again I will still have my original carb either for a core return or for a spare.:cheers:
 
MtNemoMopar said:
Well John....you have frightened me into sending mine out to be done. It is a 68 also, but for a 4/spd(glad I don't have kickdown to worry about), and I want it to work like new. SOoo....thanks for that$$$

LOL
(hopefully,you will get yours right, and I can pick your brain, to gain some of your new-found knowledge)
Click to expand...


Is that the numbers carb for your car?

If not, the 68's are sort of one year only AVS's. In that they have one center idle adjustment screw. And the adjusters at the base are lead plugged. I took the lead out of mine and couldn't get them to budge.

69-71 AVS's don't have that center adjuster, but have two idle adjusters at the base of the primaries.

The 440 carbs have primaries that are 1 11/16" as opposed to 1 7/16" with the 340 and 383's

The best article I have found on AVS's is in Mopar Action April 1990 issue

In that article by Richard Ehrenburg it lists all the Carb #'s and the jet and rod #'s. Then converts those #'s into diameters. And a bunch of other helpful specs.
 
Correct, the 340 and 383 cars got the smaller primaries on the AVS carbs from the factory. This has always been the case. Just open up a Factory Service Manual from this era and you'll see. Only the 440 got the bigger primaries. I have a '69 383 AVS carb on hand and it has the center air adjusting screw. I uncovered the lower screws and put the regular screws in there for mixture adjustment. This could have been a California model or something I don't know?
 
Make sure it's not something stupid like the igntion coil, My Friend's 340 in his cuda was doing the same things & I swapped a new coil in & it did fix it. (much cheaper than a carb also) LOL.
 
69383gts4spd said:
Make sure it's not something stupid like the igntion coil, My Friend's 340 in his cuda was doing the same things & I swapped a new coil in & it did fix it. (much cheaper than a carb also) LOL.
Click to expand...

Hello Pat, I knew this would come up, but by swapping out the little Eddie carb on my convertible she runs like a top, putting the original rebuilt AVS back on and she`s contrary again.
 
340sFastback said:
Correct, the 340 and 383 cars got the smaller primaries on the AVS carbs from the factory. This has always been the case. Just open up a Factory Service Manual from this era and you'll see. Only the 440 got the bigger primaries. I have a '69 383 AVS carb on hand and it has the center air adjusting screw. I uncovered the lower screws and put the regular screws in there for mixture adjustment. This could have been a California model or something I don't know?
Click to expand...

All 68's have the center air adjusting screw.
 
You must log in or register to reply here.
-

Back
Top