Carb Numbers

[solid gold]

Solid Gold is having her (its) carb rebuilt. It ran OK, but, it was on my list that did not get done during the resto. It is a Carter AVS #4425S. Looking up the no.,it says this carb is for a 340 A/T. I'd like to know if this right? Also,what is difference between a A/T and an MT carb.(I know that one is for a girly-matic). Solid Gold is NOT a nos. matching car,so I'm not freaking out or anything. :cool: Also, this works as a great anti-theft device. :yesnod: Thanks

 

[69hemibeep]

68 340 auto. Part of it has to do with linkage :cheers:

 

[solid gold]

Having a 340 A/T carb, does that mean anything as for as performance of the 383 M/T? I have the Air-Grabber hood and everything fits fine, so it must be the same physical size? Should I let the rebuilder know this? :huh: Am I doing my part to reduce my carbon footprint?

 

[mcmopar]

I believe that cfm rating was the same for the 340 and 383. One thing different between the a/t and m/t carbs is that in '69 the m/t carbs used a dashpot to help prevent run-on at engine shutoff. If Solid Gold is a m/t car the correct carb number would be a 4615S or SM. If it's an a/t car then the correct number is 4682. If your rebuilder is a sharp guy he'll run the numbers on the carb and fix it up accordingly. They are all physically the same size. The difference in cfm rating was achieved by larger throttle bores in the 440 carbs and different venturies in the barrels along with possible air valve secondary drizzler sizes. The 340 & 383 carbs were a "spread bore" design (smaller primary bores than secondary bores) while the 440 carb throttle bores were all the same size.
The one difference between the 340, 383 and 440 carbs will be in jet and metering rod sizes. One trick I used to do was use 340 metering rods in my 440 AVS which richened the mixture because the 340 metering rods were smaller in diameter than the 440 metering rods and allowed more fule through the jet. Since it is almost impossible to find Strip Kits for the old AVS carbs (which contained all kinds of jets and metering rods among other things) it's almost a must to scrounge around for parts carbs and cannibalize them for the necessary metering rods and jets. And no, the AFB carb metering rods won't work as well because they are "2 stage" rods - meaning they have 2 different diameters to the rod which determines how much fuel goes through the jets. The AVS metering rods are a "3 stage" design for finer fuel metering through the jet and the AFB rods and AVS rods are also different lengths if memory serves me correctly. Since you are running the 340 carb you may be running just a tad on the lean side as the jetting/metering rod setup is tuned for a 340 instead of a 383.
And if you are driving around in a 383 road runner I wouldn't be too concerned about your "carbon footprint." :basketcase:

 

[droptop]

The 340 & 383 carbs were a "spread bore" design (smaller primary bores than secondary bores).......

:huh: :huh: The only spread bore design carb that comes to mind is a thermoquad.

 

[solid gold]

Seems like McMopar is the carb guy. :worship: Yesterday,(when I delivered the carb), we discussed the nos.and correctness, etc. He said he would check into the #'s and see if he had my correct carb. If not, he can rebuild this one to work (like you were saying ) metering rods etc. Bob Kunz is rebuilding this,and he has been into carbs for over forty years(semi-retired now)(Doesn't advertise any more) It just was nice to have some info about this so I wouldn't look like a complete idiot.(I don't do my own taxes either). God Bless all of you who do all your own work! You can save alot of money.Carbs (to me) is like open heart surgery! (Only kiddin' about that carbon footprint) :jesters Solid Gold is a 4-speed.

 

[solid gold]

Found this carb # list! Hope this might help someone. http://www.mopar1.us/moparcarblist.html

 

[mcmopar]

The 340 & 383 carbs were a "spread bore" design (smaller primary bores than secondary bores).......

:huh: :huh: The only spread bore design carb that comes to mind is a thermoquad.

I used the term loosely. The 340 and 383 AVS carbs had 1-7/16" dia. primary throttle bores and 1-9/16" dia. secondary throttle bores. Thus the term "spread bore." The TQ was a true spread bore - like the QuadraJet - very small primary bores and massive secondary bores.
I'm not exactly sure about the throttle bore diameter of the 440 carbs - it was either 1-9/16" or 1-11/16" and all were the same diameter. I am leaning toward the 1-9/16" dia. as the AFB used on the 440 before 1968-9 had 1-9/16" bores and the Holley 750 had the 1-11/16" dia. throttle bores.
BTW - let me know what Bob charges for a carb rebuild/restoration. I'll be checking into multiple sources. Since I plan on running in the Pure Stock Muscle Car Drags I'll be looking for someone to do some interior flow work on it as well. I have an old Direct Connection Racing Manual from 1976 that has a lot of really good info on setting up a 383 AVS on a "hot" or "cold" cast iron manifold (manifold heat riser open [hot] or closed [cold]) which I plan on using. Hopefully it won't compromise street driveability. Of course, I could just keep my 750 Holley and run it on the street and then swap to the AVS for the drag racing.

 

[solid gold]

Got the carb. back today! Looks really nice. Here are some pics! . I overlooked having it rebuilt during restoration. :drive: All better now. :yesnod:

 

[Collin]

do you know if they used eastwoods carb renew paint on it??

 

[solid gold]

Colin, That's not paint. That's the natural cast to that carb, actually a little brighter than stock, but he said it will fade a little. He has a process.(all parts are acid tumbled,etc.) to make them look new. Went thru everything. Ran the carb on an engine. He also does Six-Packs. Top Shelf! He has been doing carbs a long time worldwide. If you, (or anybody )need ANY help, info, question or to rebuild/ restore an older carb, Pm me and I will give you his number.

 

[Roadcuda]

Found this carb # list! Hope this might help someone. http://www.mopar1.us/moparcarblist.html

Thanks for posting that list. I had it before my computer crashed last year and I couldn't find it after I had it fixed.

 

[mcmopar]

Now the carb looks as good as the car! :drool: :drool: :drool:

 

[solid gold]

Thanks- Now I think EVERYTHING was went thru! (but it's never finished) :crazy: Now that upkeep is already kickin' in. Lovin' all of it!