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71 Charger 383 Magnum carb question

Uncle Bob

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My 71 Charger 500 has 383 Magnum engine, I recently had an issue with base filling with gas due to leakage of the old Carter AVS carb, always been a fan of Holley so I replaced with Holley street warrior 600 CFM, vacuum secondaries, electric choke, single feed, engine performs quite well on throttle, but runs too rich at idle, and idle a little sketchy, tried adjusting idle mixture screws, but were set fairly close from factory, did adjust idle speed though. Contacted Holley tech and he said he thought I should run at least a 650 cfm, but may get away with what I have, anybody got any suggestions.
 
Rebuild the Carter and send the Holley packing... Overhaul on the AVS is as simple as apple pie IMO. The AVS is one of the best made Carter carbs you can get and very reliable and don’t have the bowl gasket and backfire issues of Holleys. Not trying to be rude to ya but you did ask! Lol good luck!
 
Rebuild the Carter and send the Holley packing... Overhaul on the AVS is as simple as apple pie IMO. The AVS is one of the best made Carter carbs you can get and very reliable and don’t have the bowl gasket and backfire issues of Holleys. Not trying to be rude to ya but you did ask! Lol good luck!

IMO....The origional Carter AVS is an excellent carb for general all around use. There are a few "modifications" to be done to the carb to eliminate the off idle stumble that sometimes occurs due to the emission settings and jetting and aggravated by today's ethanol blended gasoline.
The Carter AVS carb is easy to rebuild and tune using available metering jets, step up pistons and springs and metering rods. If you install a Holley in place of the origional Carter, please send it my way.....i'll give it a good home. PM me if you want to talk about mods .......
BOB RENTON
 
BTW.....some '71 383 engines used a 750 CFM Holley 4160 vacuum secondary and down leg booster venturii like a R4668, which has a reverse idle mixture circuit and a hot idle compensator valve used with A/C cars snd auto trans. Linkage and the air filter fit snd carb uses a divorced choke so everything looks origional, if that is important to you.....just an additional thought.....
BOB RENTON
 
Thanks for all the advice will consider a rebuild of Carter later, gonna try running awhile with some adjustments, did have a lot of flooding issues on cold start with the Carter, didn't have that with the electric choke on the Holley. Anyways greatly appreciate the feedback.
 
Getting all the factory settings correct on any OEM carb, AFB, AVS, T-Quad, is key, I usually spend a couple hours adjusting all the linkage and rods, and internal specs to get it set as close to stock as possible. Once on and running make sure to go through the whole process of adjusting for max vacuum with your timing, idle and carb adjustments.
 
some '71 383 engines used a 750 CFM Holley 4160 vacuum secondary and down leg booster venturii like a R4668,

R4668 = 600 CFM Holley

No Factory 750 CFM on any 1971 383

As a matter of fact throw 1968-1969-1970 383s in there also
 
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some '71 383 engines used a 750 CFM Holley 4160 vacuum secondary and down leg booster venturii like a R4668,


Bob - No Factory 750 CFM on any 1971 383

As a matter of fact throw 1968-1969-1970 383s in there also

Sorry to disagree...but....I owned 1971 Charger 500, with a HP 383 engine and A727B TF Trans...WP23N1A****** with factory A/C. The carb was a HOLLEY 4160 R-4668 and according to my build sheet, the carb was 750 CFM. The car is long gone but I still have the origional carb. The only thing lacking on the carb is the hot idle grounding screw insulator and wire assembly that operates the distributor's (aka "dizzy") retard solenoid (part of the vacuum advance diaphragm assembly) ground connection. I removed this carb when I changed the intake manifold to an Edelbrock (aka "Eddy") Torker II and went to a HOLLEY 4150 R-3310-1 780 CFM carb for a little more top end.
Some low HP 440 (Chrysler 300, station wagon, perhaps some police vehicles )applications also used a Holley 4160 650 CFM units. The differences are very subtle.....throttle bore sizes and venturi dimensions, but fuel connections were on the driver's side, entering at an up angle.....but some 1971 383 applications used a Holley.
BOB RENTON
 
"HOLLEY 4160 R-4668 and according to my build sheet"

Should have had 30 under Carb

1971 383 4bbl carburetors:

auto
Chrysler part #3512 842 w/ N96 HOLLEY model-4160 R4735A B&E-bodies orange engine
---------- B'CAST: ENG-419 & CARB-42
Chrysler part #3512 830 w/o N96 HOLLEY model-4160 R4668A B&E-bodies orange engine
---------- B'CAST: ENG-419 & CARB-30; with A/C-B'CAST: ENG-420 & CARB-30
Chrysler part #3512 844 CARTER AVS 6125S C-bodies blue engine


4-speed
Chrysler part #3512 849 w/ N96 HOLLEY model-4160 R4734A B&E-bodies orange engine
Chrysler part #3512 848 w/o N96 HOLLEY model-4160 R4667A B&E-bodies orange engine

Same as my 1971 Superbee

But where you are wrong is that the R-4668 is a 600 CFM Carburetor

No where on the build sheet does it state CFM

And it’s very easy to tell if you still have it - Measure the primary throttle plates versus the secondary throttle plates

Again the R-4668 is a 600 CFM Carburetor and I am 100% positive
Actually in all honesty, it’s probably closer to 585 CFM
 
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Thank you for your information. When I ordered and bought the '71 Charger 500, I was young and stupid and did not remove and save or make copies of the broadcast sheet. The '71 was the first year of that body style...it's still an iconic design....IMO. The only thing I still have is the memories, the FSM, and the carb.
I've researched all my Holley library for specific information re the R-4668 carb's air flow and specific pressure drop, and cannot find anything that states the 750 CFM statment...not sure where I aquired the number....To this end, I stand corrected, with regard to the carb's capacity. I appreciate your detailed information and will make copies and add it to my archives, for future reference and consideration.
Unfortunately, I do not have the broadcast sheet for my RS23V0A****** GTX, which would be a great accessory to have and show at the cruises (copies), although I've owned the car for 35+ years....but the broadcast sheet is the telling history of the vehicle. Thanks again for your info.
BOB RENTON
 
This thread caught my eye as I have quite a few of these carbs, and I have looked high and low on the web and have contacted holley to find out the cfm without any luck.
If you measure the throttle bores and calculate the total area, it looks like this:
600 cfm = 7.64 "
750 cfm = 8.96"
R4668 = 8.64"
I had one of these flowed at a carb shop and came in as 729 cfm. I don't know the test conditions, so I take that with a grain of salt.
 
This thread caught my eye as I have quite a few of these carbs, and I have looked high and low on the web and have contacted holley to find out the cfm without any luck.
If you measure the throttle bores and calculate the total area, it looks like this:
600 cfm = 7.64 "
750 cfm = 8.96"
R4668 = 8.64"
I had one of these flowed at a carb shop and came in as 729 cfm. I don't know the test conditions, so I take that with a grain of salt.
THANK YOU FOR THE INFORMATION......it is appreciated. IMO, one of the greatest unknown and most miss- understood factors is the pressure drop influence on the overall capacity. IF Holley is rated at 1.5" WC (or 3" WC, take your pick) pressure drop at specified flow, what happens if the flow is increases due to engine demand or ability? Will the carb flow more or will it stop at the published number OR will the carb continue to deliver the air flow needed at a higher pressure drop value, and how will the metering be influenced?
I believe that the test conditions (air temperature, density, barometric pressure, wet or dry conditions) will influence the overall results of test. Just a few rhetorical questions......
BOB RENTON
 
This thread caught my eye as I have quite a few of these carbs, and I have looked high and low on the web and have contacted holley to find out the cfm without any luck.
If you measure the throttle bores and calculate the total area, it looks like this:
600 cfm = 7.64 "
750 cfm = 8.96"
R4668 = 8.64"
I had one of these flowed at a carb shop and came in as 729 cfm. I don't know the test conditions, so I take that with a grain of salt.

Throttle bore to CFM is not a good correlation. A 1 3/4" throttle bore carbs can flow from 800 to 1050 CFM. Venturi, booster, throttle shafts and throttle blades are some of the key variables that will determine flow.
 
My 71 Charger 500 has 383 Magnum engine, I recently had an issue with base filling with gas due to leakage of the old Carter AVS carb, always been a fan of Holley so I replaced with Holley street warrior 600 CFM, vacuum secondaries, electric choke, single feed, engine performs quite well on throttle, but runs too rich at idle, and idle a little sketchy, tried adjusting idle mixture screws, but were set fairly close from factory, did adjust idle speed though. Contacted Holley tech and he said he thought I should run at least a 650 cfm, but may get away with what I have, anybody got any suggestions.
 
Throttle bore to CFM is not a good correlation. A 1 3/4" throttle bore carbs can flow from 800 to 1050 CFM. Venturi, booster, throttle shafts and throttle blades are some of the key variables that will determine flow.

For sure it's more than just the throttle bores. Add in the venturi sizes and I would think those are the main drivers in cfm. Anyway, in this case the venturis are also larger on the 4668 than the 600.
 
Did you discuss at all with Holley fuel supply? Pressure and volume mix-ups could make float bowls a tricky concern. The best mix could take some swapping around.
 
Most if not all 1971 383 Magnums left the factory with the Holley 4160

And most of those R4668 ended up in the garbage before they left the dealer lot

Maybe that’s why they are so rare today

Quote



I will provide further first hand back-up of the existence of factory provided Carter conversion kits for the Holley 4160 applications, performed the conversion many times myself during my time at dealers back then. They were packaged as complete kits, fuel lines, choke springs, any other hardware required, fully covered if under warranty. Installed correctly, appeared completely factory installed. Can�t tell you just how many 4160�s wound up in the trash, considered pure junk then by those who serviced them and many under hood fires were blamed directly on them.

They where replaced at the dealers with the Carter AVS 6125s - That was the conversion
kit

I have seen flow tests of 585 cfm decades ago
 
Most if not all 1971 383 Magnums left the factory with the Holley 4160

And most of those R4668 ended up in the garbage before they left the dealer lot

Maybe that’s why they are so rare today

Quote



I will provide further first hand back-up of the existence of factory provided Carter conversion kits for the Holley 4160 applications, performed the conversion many times myself during my time at dealers back then. They were packaged as complete kits, fuel lines, choke springs, any other hardware required, fully covered if under warranty. Installed correctly, appeared completely factory installed. Can�t tell you just how many 4160�s wound up in the trash, considered pure junk then by those who serviced them and many under hood fires were blamed directly on them.

They where replaced at the dealers with the Carter AVS 6125s - That was the conversion
kit

I have seen flow tests of 585 cfm decades ago
VERY INTERESTING.....never heard of Chrysler's wholesale changing of the Holley R4668 to Carter 6125-SA. Found on on eBay for $ 150 + shipping (very rough condition). Since the origional Holley was certified as OEM as supplied, to pass the EPA certification requirements for that year. It would be interesting to see the exemption granted to Chrysler, and the reasoning and the test documentation and what snd how the requirement was achieved. True, emission requirements were substantially less strenuous then, but they still needed to be tested to develop the required documentation for EPA acceptance, especially California. For one, I'm very interested......out of curiosity....
BOB RENTON
 
Most if not all 1971 383 Magnums left the factory with the Holley 4160

And most of those R4668 ended up in the garbage before they left the dealer lot

Maybe that’s why they are so rare today

Quote



I will provide further first hand back-up of the existence of factory provided Carter conversion kits for the Holley 4160 applications, performed the conversion many times myself during my time at dealers back then. They were packaged as complete kits, fuel lines, choke springs, any other hardware required, fully covered if under warranty. Installed correctly, appeared completely factory installed. Can�t tell you just how many 4160�s wound up in the trash, considered pure junk then by those who serviced them and many under hood fires were blamed directly on them.

They where replaced at the dealers with the Carter AVS 6125s - That was the conversion
kit

I have seen flow tests of 585 cfm decades ago[/QU

So what was exactly the problem with the holleys, as you see it since you were there ?
 
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