440 Six Pack Carb Numbers: Mopar Carburetor Identification

The 440 Six Pack or Six Barrel carburetors are often talked about. One of the most common questions is their list numbers or date codes. Let’s answer, what are the 440 Six Pack carb numbers?

The following are the 440 Six Pack carburetor numbers for all years:

R-4393A: 1969 front
R-4394A: 1969 rear
R-4391A: 1969 center/manual
R-4392A: 1969 center/auto
R-4382A: 1970 front/C.A.S
R-4383A: 1970 rear/C.A.S.
R-4375A: 1970 center/manual/C.A.S.
R-4376A: 1970 center/auto/C.A.S.
R-4175A: 1970 front/E.C.S./Cali
R-4365A: 1970 rear/E.C.S./Cali
R-4374A: 1970 center/manual/E.C.S./Cali
R-4144A: 1970 center/auto/E.C.S./Cali
R-4671A: 1971 front
R-4672A: 1971 rear
R-4669A: 1971 center/manual
R-4670A: 1971 center/auto
R-6405A: 1972 front
R-6406A: 1972 rear
R-6403A: 1972 center/manual
R-6404A: 1972 center/auto

The remainder of this article provides detailed information about each carburetor. This includes the brand, model, cfm, jet sizes and date codes. Also, there’s some interesting information about 1972.

Six Pack Carb Numbers (Holley List Numbers)

The carburetor numbers or list numbers will be the same whether it’s from a Six Pack (Dodge) or a Six Barrel (Plymouth) car.

The carbs used on all Six Packs were made by Holley. The list numbers are usually stamped on the carburetor body and proceeded by the word ‘LIST’ or the letter ‘R.’ Four numbers are directly above it indicating the date code.

On the center carb the list number is located on the rear, left of the air horn close to the top.

On the front and rear carbs, the list number can be found on the rear, left of the main body close to the top.

If there is a third number or a part number, typically that indicates the carb is a reproduction or a replacement carb produced at a later date.

440 Six Pack Carb Numbers and Specs

R-4391A

Application: 1969 440 Six Pack/Six Barrel center carburetor
Transmission: Manual
Model: Holley 2300 series 2-barrel
CFM: 350
Throttle bore: 1 1/2″
Main venturi: 1 3/16″
Standard jet: 64
- 1 size lean: 62
- 2 size lean (5,000-10,000 ft.): 60
Float: externally adjustable/center hung
Choke type: Well
- Control: Coil spring
- Setting: 2-notches rich

R-4392A

Application: 1969 440 Six Pack/Six Barrel center carburetor
Transmission: Automatic
Model: Holley 2300 series 2-barrel
CFM: 350
Throttle bore: 1 1/2″
Main venturi: 1 3/16″
Standard jet: 63
- 1 size lean: 61
- 2 size lean (5,000-10,000 ft.): 59
Float: externally adjustable/center hung
Choke type: Well
- Control: Coil spring
- Setting: 2-notches rich

R-4393A

Application: 1969 440 Six Pack/Six Barrel front carburetor
Transmission: Manual or Automatic
Model: Holley 2300 series 2-barrel
CFM: 500
Throttle bore: 1 3/4″
Main venturi: 1 9/16″
Float: externally adjustable/center hung

R-4394A

Application: 1969 440 Six Pack/Six Barrel rear carburetor
Transmission: Manual or Automatic
Model: Holley 2300 series 2-barrel
CFM: 500
Throttle bore: 1 3/4″
Main venturi: 1 9/16″
Float: externally adjustable/center hung

R-4375A

Application: 1970 440 Six Pack/Six Barrel center carburetor
Transmission: Manual
Model: Holley 2300 series 2-barrel
CFM: 350
Throttle bore: 1 1/2″
Main venturi: 1 3/16″
Standard jet: 64
- 1 size lean: 63
- 2 size lean (5,000-10,000 ft.): 62
Float: externally adjustable/center hung
Choke type: Well
- Control: Coil spring
- Setting: 2-notches rich

R-4376A

Application: 1970 440 Six Pack/Six Barrel center carburetor
Transmission: Automatic
Model: Holley 2300 series 2-barrel
CFM: 350
Throttle bore: 1 1/2″
Main venturi: 1 3/16″
Standard jet: 63
- 1 size lean: 62
- 2 size lean (5,000-10,000 ft.): 61
Float: externally adjustable/center hung
Choke type: Well
- Control: Coil spring
- Setting: 2-notches rich

R-4382A

Application: 1970 440 Six Pack/Six Barrel front carburetor
Transmission: Manual or Automatic
Model: Holley 2300 series 2-barrel
CFM: 500
Throttle bore: 1 3/4″
Main venturi: 1 9/16″
Float: externally adjustable/center hung

R-4383A

Application: 1970 440 Six Pack/Six Barrel rear carburetor
Transmission: Manual or Automatic
Model: Holley 2300 series 2-barrel
CFM: 500
Throttle bore: 1 3/4″
Main venturi: 1 9/16″
Float: externally adjustable/center hung

R-4374A

Application: 1970 440 Six Pack/Six Barrel center carburetor
E.C.S. (California)
Transmission: Manual
Model: Holley 2300 series 2-barrel
CFM: 350
Throttle bore: 1 1/2″
Main venturi: 1 3/16″
Standard jet: 64
- 1 size lean: 63
- 2 size lean (5,000-10,000 ft.): 62
Float: externally adjustable/center hung
Choke type: Well
- Control: Coil spring
- Setting: 2-notches rich

R-4144A

Application: 1970 440 Six Pack/Six Barrel center carburetor
E.C.S. (California)
Transmission: Automatic
Model: Holley 2300 series 2-barrel
CFM: 350
Throttle bore: 1 1/2″
Main venturi: 1 3/16″
Standard jet: 63
- 1 size lean: 62
- 2 size lean (5,000-10,000 ft.): 61
Float: externally adjustable/center hung
Choke type: Well
- Control: Coil spring
- Setting: 2-notches rich

R-4175A

Application: 1970 440 Six Pack/Six Barrel front carburetor
E.C.S. (California)
Transmission: Manual or Automatic
Model: Holley 2300 series 2-barrel
CFM: 500
Throttle bore: 1 3/4″
Main venturi: 1 9/16″
Float: externally adjustable/center hung

R-4365A

Application: 1970 440 Six Pack/Six Barrel rear carburetor
E.C.S. (California)
Transmission: Manual or Automatic
Model: Holley 2300 series 2-barrel
CFM: 500
Throttle bore: 1 3/4″
Main venturi: 1 9/16″
Float: externally adjustable/center hung

R-4669A

Application: 1971 440 Six Pack/Six Barrel center carburetor
Transmission: Manual
Model: Holley 2300 series 2-barrel
CFM: 350
Throttle bore: 1 1/2″
Main venturi: 1 3/16″
Standard jet: 63
- 1 size lean: 62
- 2 size lean (5,000-10,000 ft.): 61
Float: externally adjustable/center hung
Choke type: Well
- Control: Coil spring
- Setting: 2-notches rich

R-4670A

Application: 1971 440 Six Pack/Six Barrel center carburetor
Transmission: Automatic
Model: Holley 2300 series 2-barrel
CFM: 350
Throttle bore: 1 1/2″
Main venturi: 1 3/16″
Standard jet: 63
- 1 size lean: 62
- 2 size lean (5,000-10,000 ft.): 61
Float: externally adjustable/center hung
Choke type: Well
- Control: Coil spring
- Setting: 2-notches rich

R-4671A

Application: 1971 440 Six Pack/Six Barrel front carburetor
Transmission: Manual or Automatic
Model: Holley 2300 series 2-barrel
CFM: 500
Throttle bore: 1 3/4″
Main venturi: 1 9/16″
Float: externally adjustable/center hung

R-4672A

Application: 1971 440 Six Pack/Six Barrel rear carburetor
Transmission: Manual or Automatic
Model: Holley 2300 series 2-barrel
CFM: 500
Throttle bore: 1 3/4″
Main venturi: 1 9/16″
Float: externally adjustable/center hung

1972 440 Six Pack Carb Numbers

A ’72 classic Mopar doesn’t get much love, but maybe this classic should.

Yes, a few 1972 Six Pack/Six Barrel cars snuck out of the factory in 1972. Originally Chrysler planned to continue the Six Pack carb option.

Evidence of this is shown in the 1972 sales brochures and service manuals printed before the option was canceled.

For more details on the 1972 cars check out my article, Cars With a 440 Six Pack From the Factory. I include pictures of the brochures.

1972 Holley 440 Six Barrel carbs, 6403 6404 6405 6406, from the Plymouth service manual. — 1972 Holley 440 Six Barrel carbs 6403 6404 6405 6406 from the Plymouth service manual

The following are the 1972 Six Pack carbs and their specifications. The rarest Six Pack carburetors.

R-6403A

Application: 1972 440 Six Pack/Six Barrel center carburetor
Transmission: Manual
Model: Holley 2300 series 2-barrel
CFM: 350
Throttle bore: 1 1/2″
Main venturi: 1 3/16″
Standard jet: 62
- 1 step lean: 61
- 2 step lean (5,000-10,000 ft.): 60
Float: externally adjustable/center hung
Choke type: Automatic
- Control: Thermostatically controlled with fixed setting

R-6404A

Application: 1972 440 Six Pack/Six Barrel center carburetor
Transmission: Automatic
Model: Holley 2300 series 2-barrel
CFM: 350
Throttle bore: 1 1/2″
Main venturi: 1 3/16″
Standard jet: 62
- 1 step lean: 61
- 2 step lean (5,000-10,000 ft.): 60
Float: externally adjustable/center hung
Choke type: Automatic
- Control: Thermostatically controlled with fixed setting

R-6405A

Application: 1972 440 Six Pack/Six Barrel front carburetor
Transmission: Manual or Automatic
Model: Holley 2300 series 2-barrel
CFM: 500
Throttle bore: 1 3/4″
Main venturi: 1 9/16″
Float: externally adjustable/center hung

R-6406A

Application: 1972 440 Six Pack/Six Barrel rear carburetor
Transmission: Manual or Automatic
Model: Holley 2300 series 2-barrel
CFM: 500
Throttle bore: 1 3/4″
Main venturi: 1 9/16″
Float: externally adjustable/center hung

440 Six Pack Date Code

The date code numbers will be the same whether it’s from a Six Pack (Dodge) or a Six Barrel (Plymouth) car.

The carbs used on all Six Packs were made by Holley. The date code numbers are usually stamped on the carburetor body and found above the list number.

On the center carb the date code is located on the rear, left of the air horn close to the top.

On the outboard, front and rear carbs, the carb date can be found on the rear, left of the main body close to the top.

Carb Date Numbers

The Six Pack Holley date code consists of four numbers. The carb date does not go by the Chrysler 10,000 day calendar.

The first three numbers indicate the day of the year and the fourth number indicates the year.

Therefore, a date code of 3649 from a 1970 carb indicates the 364th day of the year (December 24th). The 9 indicates the year 1969 (December 24, 1969). I hope the employees got to go home early that day.

The 1969 Six Pack front carb in the picture above indicates a date code of 0739.

0739= March 14, 1969

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More Mopar Carburetor Articles

I first learned about 440 Six-Pack carbs and their numbers when I owned a Six Barrel engine 39 years ago. I’ve been researching Mopars and the 440 Six Pack engines for approximately 40 years. My research includes personal experience, books, manuals, articles, magazines, webinars, live events and videos.