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Carb for 68 Roadrunner?

Ed Martin

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Any recommendations for a carb (original Carter AVS or Holley) for a stock 383? Years ago I replaced the original manifold with a Torker single plane manifold and Holley 6909 carb. Now want to put the original manifold back with a new carb (because of problems with the 6909). I'm looking for good low end drivability. Don't know about the availability of the Carter AVS. Holley recommends the Classic 600 cfm 80457SA. Any help is appreciated.
 
The Carter design was a very good one. They were bought out by Edelbrock. 600 CFM is all a 383 needs. Vacuum secondaries are best for street use and they work well at the track too.
 
The carter doesn't have vaccum secondaries but it is still a good carb. The edlebrock thunder series is a repop of the old avs but I like a holley on these cars. My recomendation would be a street avenger series, you can get them with an electric choke and they come with the quick change tops for the secondary springs so you can tune the spring in a snap. I've run a couple of them with no regrets.
 
for a stock type replacement i'd use the edelbrock 650avs. it is possible to convert these to the stock type choke mechanism if you have a donor carb.
 
The carter doesn't have vaccum secondaries but it is still a good carb. The edlebrock thunder series is a repop of the old avs but I like a holley on these cars. My recomendation would be a street avenger series, you can get them with an electric choke and they come with the quick change tops for the secondary springs so you can tune the spring in a snap. I've run a couple of them with no regrets.
Sorry Bill, but the Carter AVS is a vacuum secondary carb. You can check it out here: https://www.allpar.com/fix/fuel/carter-AVS.html

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Sorry Bill, but the Carter AVS is a vacuum secondary carb. You can check it out here: https://www.allpar.com/fix/fuel/carter-AVS.html

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I stand corrected my friend, the mechanism and operation is completely different from a holley in that when the secondaries start to mechanically open on the avs, it causes a vacuum on the air door which controls the amount of air coming in thus preventing a lean out before the fuel catches up....so you are correct as stated Sir.
 
I run a 600cfm edelbrock 1406 electric choke model on my pretty much stock 383, plugs burn nice , no stumble or bog. It will spin the tires and run 120. I like it, once its set, its set.
 
Gentlemen,
In my opinion, OEM Carter AVS carb (Air Valve Secondary) is an excellent carb and has 1-7/16" primary and 1-11/16" secondary bores. I believe its rated at approximately 750 CFM.
It is very easey to rejet with an Edlebrock kit.
The only real problem with the original carb is it is lean off idle due to emission requirements. The carb has an adjustable "off idle air bleed" that can be used to richen the mixture by plugging the air bleed with small split shot sinkers. This carb has a single idle mixture screw, which is basically an air bleed not a fuel feed. If you're looking for originality, they can be found on eBay or other internet suppliers.
BTW...when Carter went out of business, Edlebrock bought the license from AMF to produce the carbs. AFBs and AVS carbs are an on demand secondary either via velocity weighted secondary valves immediately above the secondary butterfly valves but below the secondary booster venturii or a spring tension on the air door. Just about ALL Mopar carbs use a divorced choke system. If it were my car, I'd look for an original carb. Others will have different opinions.
Bob Renton
 
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