Carter Aluminum Four-barrel (AFB) Carburetors

(includes ID numbers, specifications, and CFM flow rates)

Carter AFB Carburetor

Introduction

This article discusses Carter AFB carburetors and how to gauge CFM based off confirmed examples. The difficulty with Carter AFB carburetors is that very few were ever rated by the factory for CFM and no complete list is available publicly. There are relatively complete lists of carburetor models and what engine they were originally used on, which I have compiled and edited below, but they do not include CFM ratings. However, there are methods to gauge CFM. Of possible interest, see my other technical articles on rebuilding Carter AFB carburetors and on selecting and tuning Carter AFB carburetors.

Carter AFB CFM Specifications

The best way to identify the approximate CFM of AFB carburetors is a mix of the OEM catalog of engines and inductive reasoning using dimensions from known CFMs in relationship to the engine displacement on which the carburetors were originally used. Ideally, I can measure the throttle and venturi bores of the carburetor before purchasing, but many times when purchasing online I am not able to get those exact measurements. When I don’t have those measurements, I do some educated guessing until I have the carburetor in my hands and can mike the venturis.

For example, I know from the dimensions below and the OEM catalog that a 450 CFM 3252S with 1-7/16” square bores was used on early 60’s 383 and low-performance 413 engines. A 470 CFM 3853S with 1-7/16” primary 1-9/16” secondary bores was used on the 273. A 566 CFM 3611S with 1-7/16” primary 1-9/16” secondary bores came on mid-60’s 383 and 426 wedge engines. However, once we get into the 600 CFM range from the known carburetors below, the OEM catalog shows higher performance models of 340s, 413 ram-induction, and 426 Hemis. Putting all this information together, when I am looking for an AFB and don’t have venturi or throttle bore measurements, I can infer that late-50’s and early 60’s AFBs that came on 313, 318, 326, 350, 354, 361, 383, 392, and low-performance 413 engines likely have between 400 and 500 CFM. Mid-60’s AFBs that came on 273, 383, and low-performance 413 engines likely have between 470 and 566 CFM. AFBs that came on 340, high-performance 413, 426 hemi and wedge, and 440 engines likely have 600 CFM and above.

For most single-carburetor stock and mild A-block builds, finding an AFB model from a late 50’s – early-60’s A, B, or low-performance RB engine will be 400 – 566 CFM and a good choice for the engine after properly jetted and tuned. These carburetors will also be a good place to look for dual-quad setups. For higher-performance single-carburetor A-block builds, finding an AFB that came on mid- to late-60’s LA340/RB engines will likely yield 600 – 728 CFM. Once the carburetor is in my hand, I can dial in the CFM using the known throttle bore and venturi dimensions detailed below.

The following Mopar AFB data with CFM come from Paul Cesarine who passed away in 2016 long before his database was finished. He flow-tested these carburetors to confirm their actual flow and was known as a trustworthy source of carburetor information. I have measured and have collected measurements on other AFB throttle bores and have listed them to help those searching, although I do not have venturi diameters for all carburetors. Keep in mind that Carter made hundreds of AFB models for multiple auto makers, so researching other auto maker AFB models can open more options than focusing just on Mopar models.

Confirmed Mopar Carter AFB CFM Data

450 (CFM confirmed)

3252S, 3249S

  • Throttle Body Sizes: 1 7/16″ x 1 7/16″
  • Venturi Sizes: 1.186″ x 1.186″

Other AFB with throttle bores 1-7/16″ x 1-7/16″ (CFM not confirmed)

  • 2448S (dual quad)
  • 2787S
  • 3253S
  • 3257S

460 (CFM confirmed)

3853S

465 (CFM confirmed)

2790S (front dual quad), 3258S (front dual quad)

  • Throttle Body Sizes: 1 7/16″ x 1 9/16″
  • Venturi Sizes: 1.093″ x 1.125″

470 (CFM confirmed)

3853S, 3854S, 4199S, 4120S, 4294S, 4295S

  • Throttle Body Sizes: 1 7/16″ x 1 9/16″
  • Venturi Sizes: 1.063″ x 1.250″

475 (CFM confirmed)
AFB 2791S (rear dual quad), 3259S (rear dual quad)

  • Throttle Body Sizes: 1 7/16″ x 1 9/16″
  • Venturi Sizes: 1.093″ x 1.125″

537 (CFM confirmed)

4298S, 4299S

  • Throttle Body Sizes: 1 7/16″ x 1 9/16″
  • Venturi Sizes: 1.186″ x 1.313″

566 (CFM confirmed)

3437S

  • Throttle Body Sizes: 1 7/16″ x 1 9/16″
  • Venturi Sizes: 1.186″ x 1.313″

566 (CFM confirmed)

3611S

  • Throttle Body Sizes: 1 7/16″ x 1 9/16″
  • Venturi Sizes: 1.186″ x 1.313″

566 (CFM confirmed)

3859S, 3860S

  • Throttle Body Sizes: 1 7/16″ x 1 9/16″
  • Venturi Sizes: 1.186″ x 1.313″

566 (CFM confirmed)

4130S, 4131S

  • Throttle Body Sizes: 1 7/16″ x 1 9/16″
  • Venturi Sizes: 1.186″ x 1.563″

Other AFB with throttle bores 1-7/16″ x 1-9/16″ (CFM not confirmed)

  • 2797S
  • 3256S
  • 3478S
  • 3611S
  • 3614S
  • 3856S
  • 3871S
  • 4133S
  • 4742S
  • 4911S

600 (CFM confirmed)

3447S

  • Throttle Body Sizes: 1 7/16″ x 1 11/16″
  • Venturi Sizes: 1.186″ x 1.563″

600 (CFM confirmed)

4139S (Front) 4140S (Rear)

  • Throttle Body Sizes: 1 7/16″ x 1 11/16″
  • Venturi Sizes: 1.186″ x 1.563″

700 (CFM confirmed)

3705SA

  • Throttle Body Sizes: 1 11/16″ x 1 11/16″
  • Venturi Sizes: 1.437″ x 1.563′

728 (CFM confirmed)

4326S, 4327S

  • Throttle Body Sizes: 1 11/16″ x 1 11/16″
  • Venturi Sizes: 1.437″ x 1.586″

Mopar Carter AFB Model, Year, Engine, and Notes (not a complete list)

2448 57 392
2650 58 354
2651 58 392
2686 57 354
2787 59 383/413 Automatic
2790 59 413 2×4 Front
2791 59 413 2×4 Rear
2794 59 383/413
2797 59 383/413
2798 59 413 2×4 Front
2799 59 413 2×4 Rear
2805 58 354
2806 58 392
2836 58 354
2854 59 383/413 Police
2903 60 413
2927 60 413
2955 Marine
2991 60 318
3108 61 413
3134 61 413
3247 61-62 318/361
3249 61-62 318/361
3251 62 413
3252 61-62 383/413
3253 61-62 383/413
3257 62 413
3258 62 413 2×4 Front
3259 62 413 2×4 Rear
3374 62 383 Police
3375 62 383 Police
3437 63 383 Police
3447 63 413 Ram Induction
3478 63 383/413 Police
3505 63 64 413
3520 63 383 Automatic (Canada)
3611 64 383/426
3612 64 383 Automatic (Canada)
3613 64 383 Automatic (Canada)
3614 64 413
3615 64 413
3644 64 413
3660 Marine
3705 64 426 2×4
3853 65 273 Manual
3854 65 273 Automatic
3855 65 383 Manual
3856 65 383 Automatic
3858 65 413
3859 65 383/413/426 Manual
3860 65 383/413/426 Automatic
3861 65 426 2×4
3871 65 413
4119 66 273 Manual
4120 66 273 Automatic
4121 66 273 Manual CA
4122 66 273 Automatic CA
4130 66 383/426 Manual
4131 66 383/426 Automatic
4132 66 383 Manual CA
4133 66 383 Automatic CA
4136 64-67 426/440 Manual CA
4137 64-67 426/440 Automatic CA
4139 67 426 2×4 Front
4140 early-67 426 2×4 Rear
4200 64 383 Automatic Canada
4294 67 273 Manual
4295 67 273 Automatic
4298 67 383 Manual
4299 67 383 Automatic
4304 67 273 Manual CA
4305 67 273 Automatic CA
4309 67 383 Manual CA
4310 67 383 Automatic CA
4311 67 440 Manual CA
4312 67 440 Automatic CA
4318 66 383 Automatic CA
4324 67 426 2×4 Front CA
4325 67 426 2×4 Manual Rear CA
4326 67 440 Manual
4327 67 440 Automatic
4328 67 440 Manual P/P CA
4329 67 440 Automatic P/P CA
4330 68 440 Automatic w/ Air Conditioning
4343 late-67 426 2×4 Rear
4402 67 426 2×4 Automatic Rear CA
4430 68 426 2×4 Front
4431 68 426 2×4 Manual Rear
4432 68 426 2×4 Automatic Rear
4619 69 426 2×4 Front
4620 69 426 2×4 Manual Rear
4621 69 426 2×4 Automatic Rear
4742 70-early-71 426 2×4 All/T Front
4745 70-early-71 426 2×4 Manual Rear
4746 70 426 Automatic Rear
4911 65-69 383/413
4969 late-71 426 2×4 Manual Rear
4970 late-71 426 2×4 Automatic Rear
4971 late-71 426 2×4 Automatic Front
6310 Marine
Aftermarket Carter AFB
9400 400 CFM
9410 400 CFM
9502 500 CFM no choke, GM linkage
9511 500 CFM Mopar linkage
9605 600 CFM, manual choke, GM linkage
9625 625 CFM
9626 625 CFM
9627 625 CFM
9635 625 CFM
9636 625 CFM
9637 625 CFM, electric choke carb, Ford linkage
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