Autolite 2100, 4100 and 1100 Carburetor Identification Guide

From 1957 into the 1970s, Ford fitted Autolite carburetors to most of its cars and trucks: the 1100 one-barrel on sixes, the 2100 two-barrel on most V8s and, until 1967, the 4100 four-barrel. Each one left the factory with a small tag stamped with a Ford number such as C6ZF-A. Find that number in the table below to see the carburetor's venturi size, its airflow rating and what Ford listed it for. To check whether that size suits your engine, use the carburetor CFM calculator.

Where to find the tag and venturi size

The tag is a small stamped metal tab held on by one of the screws that fasten the top of the carburetor (the air horn) to the main body. The Ford number is stamped across it. Many tags also carry a short build-date code, which isn't part of the number.

Tags were easy to lose during a rebuild, and rebuilders sometimes moved them from one carburetor to another, so check the venturi size too. On the 2100 and 4100 it's stamped into the side of the main body as a decimal, such as 1.08 or 1.14. If the tag is gone, the venturi size, the engine and the details in the Notes column (choke type, kickdown lever) narrow it down.

How to read a Ford carburetor number

From 1960 on, Ford's numbers follow one pattern. Take C6ZF-A:

The full number in Ford's parts books puts the basic part number between them: C6ZF-9510-A, where 9510 means carburetor. The table search accepts either form, with or without dashes, so C6ZF-A, C6ZF-9510-A and c6zfa all find the same row.

The car line letters on these carburetors:

• A: full-size Ford (Galaxie, LTD)
• D: Falcon
• G: Mercury Comet
• M: full-size Mercury
• O: Fairlane, later Torino
• S: Thunderbird
• T: Ford truck
• U: Econoline and Bronco
• W: Cougar
• Z: Mustang
• P: a replacement sold through Ford's parts system rather than fitted at the factory
• F: built for another company. The F-line 2100s in the table were for AMC's 304 V8.

The car line letter only says which car line released the part first. A Z carburetor can be on a Falcon, and the 1964½ Mustang's four-barrel was a Comet number (C4GF-AE). The Vehicle column lists every car each number was listed for.

Numbers from 1957–59 don't follow this pattern. They're either Autolite's own letter codes, such as ECG or EDB-K, or seven-digit Ford numbers such as 5752306.

Autolite 1100 one-barrel

The 1100 was Ford's one-barrel for its small sixes from 1963 to 1969: the 144, 170 and 200, plus some truck and full-size car applications of the 223 and 262. The venturi size went up with the engine:

All figures are rated at 3.0 inches of mercury (see Sizes and CFM). The 1.00 and 1.10 figures come from a single source, so treat them as approximate.

For 1968, Ford went back to a 1.10 venturi on the 200 and dropped the spark control valve. Carburetors from 1967–69 also carry a second diaphragm on the side, a dashpot that keeps the engine from stalling when the throttle snaps shut.

The 1101, used on the 250 six in 1969, looks similar but isn't the same carburetor: its throttle bore is 1-11/16 inches against the 1100's 1-7/16, and it flows roughly 200 to 215 cfm. Around 1970 Ford replaced both with the Carter YF.

We haven't found a reliable list of 1100 numbers with their original applications, so 1100s aren't in the code table. Identify one by its venturi stamp and the engine it came on.

Autolite 2100 two-barrel

The 2100 arrived in 1957 and was Ford's standard two-barrel until 1973, with replacement numbers listed through 1975. It went on nearly every Ford V8 of the period in two-barrel form: the 272, 292 and 332 Y-blocks, the 221, 260, 289 and 302 small blocks, the 351 and 400, and the 352, 360 and 390 FE big blocks. AMC also bought it for the 304.

Its boost venturis spray fuel from a ring of small holes rather than a single nozzle, which breaks the fuel up finely. Most have an automatic choke; trucks and some replacement units have a manual choke. The base uses the same bolt pattern as the Holley two-barrel. In the mid-1970s it was replaced by the Motorcraft 2150.

The 2100 came in eight venturi sizes, from 0.98 to 1.33 (190 to 424 cfm).

Autolite 4100 four-barrel

The 4100 ran from 1957 to 1967, with some 428 Police Interceptor numbers listed through 1968. It's a square-flange four-barrel whose secondaries are opened by linkage from the primaries.

Most 4100s have one of two venturi sizes:

• 1.08 (480 cfm): the 289 four-barrel from 1964½, plus some 390s.
• 1.12 (600 cfm): the 352, 390 and 428 Police Interceptor, and the 289 High Performance (the K-code), most of which had a manual choke.

The 1958 Mercury 383 had two others: a 1.06 on the low-torque version and a 1.19 (669 cfm) on the high-torque version, the largest carburetor Autolite built.

From 1967, Ford began replacing the 4100 with the Autolite 4300, a different design.

Sizes and CFM

One- and two-barrel carburetors are rated at a pressure drop of 3.0 inches of mercury, and four-barrels at 1.5. The higher test vacuum pulls more air through, so a 2100's number looks big next to a four-barrel's. To compare them on the same basis, divide the two-barrel rating by 1.414 (the calculator's rating converter does this): a 287 cfm 2100 is about 203 cfm by four-barrel rules, and a 300 cfm 2100 is about 212.

The carburetor CFM calculator works out what an engine needs and compares it with every Autolite size on the same basis.

Which Autolite did my Mustang have?

Later four-barrel Mustangs, such as the 390, 428 Cobra Jet and 351 four-barrel, used Holley or Autolite 4300 carburetors, which aren't covered here.

What the columns mean

• Ford Number: the number on the tag. Under it is the full number from Ford's parts books.
• Venturi: the venturi size in inches, as stamped on the main body.
• CFM: the rated airflow for that venturi size. 2100s are rated at 3.0 inches of mercury and 4100s at 1.5.
• Year: the model years the number was listed for. 1964½ is the early 1964 Mustang.
• Engine: displacement in cubic inches. HiPo is the 289 High Performance.
• Vehicle: the cars and trucks it was listed for. Service replacement means it was sold as a replacement part rather than fitted at the factory.
• Notes: Kickdown lever marks a throttle lever with the tab for an automatic transmission's kickdown rod, and No kickdown lever a version without it. Manual choke, Automatic choke, Manual trans and Automatic trans mark versions built for those setups. Throttle control marks a version listed with a throttle control on the linkage. No Thermactor marks a version for engines without Thermactor air injection, the early emissions system.

A blank cell means nothing is noted. Ford often used one number on more cars than it was first listed for, and replaced older numbers with newer ones, so treat the Vehicle column as a guide, not a complete list.

Is a C6ZF-A a 2100 or a 4100?

A C6ZF-A is a 4100 four-barrel with a 1.08 venturi, rated at 480 cfm. It was listed for the 1966 Mustang and Falcon with the 289 four-barrel. The rest of the C6ZF family is in the table: C6ZF-B, D and E are the same size, while C6ZF-C and C6ZF-F are 1.12 (600 cfm) carburetors for the 289 High Performance. Search for any number in the table, or select a row's link icon to share a link straight to it. The carburetor CFM calculator opens on a stock 289, so it shows how a 480 cfm 4100 compares with what that engine needs.

Mustang Autolite carburetor codes

Every code in the table below that lists a Mustang, 1964½ to 1973. Many were shared with the Falcon, Fairlane, Comet and Cougar; select a code to see every car it was listed for.

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Ford Number	Carb	Venturi	CFM	Year	Engine	Notes
C3OF-AJ	4100	1.12	600	1963–64	289 HiPo	Manual trans
C4GF-AE	4100	1.08	480	1964½	289	Manual trans
C4GF-AF	4100	1.08	480	1964½	289	Automatic trans
C4OF-AL	4100	1.12	600	1964	289 HiPo
C4ZF-C	4100	1.08	480	1964½	289
C4ZF-E	2100	1.01	240	1964½	260
C4ZF-F	2100	1.01	240	1964½	260
C4ZF-R	2100	1.01	240	1964½	260
C5OF-J	4100	1.12	600	1965	289 HiPo
C5ZF-A	2100	1.14	300	1965	289
C5ZF-B	2100	1.14	300	1965	289
C5ZF-C	4100	1.08	480	1965	289
C5ZF-D	4100	1.08	480	1965	289
C5ZF-E	4100	1.08	480	1965	289
C5ZF-F	4100	1.08	480	1965	289
C6DF-A	2100	1.14	300	1966	289
C6DF-B	2100	1.14	300	1966	289
C6DF-F	2100	1.14	300	1966	289
C6PF-F	2100	1.01	240	1962–66	221/260/289
C6PF-H	4100	1.08	480	1964–66	289/428	Kickdown lever
C6ZF-A	4100	1.08	480	1966	289
C6ZF-B	4100	1.08	480	1966	289
C6ZF-C	4100	1.12	600	1966–67	289 HiPo
C6ZF-D	4100	1.08	480	1966	289
C6ZF-E	4100	1.08	480	1966	289
C6ZF-F	4100	1.12	600	1966	289 HiPo
C7DF-F	2100	1.02	245	1967	289
C7DF-N	2100	1.14	300	1967	289
C7DF-R	2100	1.14	300	1967	289
C7DF-S	2100	1.02	245	1967	289
C7DF-V	2100	1.14	300	1967	289
C8AF-AK	2100	1.08	287	1968	302
C8AF-BD	2100	1.08	287	1968	302	Kickdown lever
C8AF-L	2100	1.08	287	1968	302	Kickdown lever
C8ZF-G	2100	1.08	287	1968	289/302
C9AF-A	2100	1.08	287	1969	289/302	Kickdown lever
C9AF-C	2100	1.23	356	1969	390	Kickdown lever
C9AF-J	2100	1.23	356	1969	351
C9AF-Z	2100	1.23	356	1969	351	Kickdown lever
C9OF-C	2100	1.23	356	1969	351
C9ZF-A	2100	1.23	356	1969	351
C9ZF-B	2100	1.23	356	1969	351	Kickdown lever
C9ZF-G	2100	1.08	287	1969	302
D1ZF-AD	2100	1.08	287	1971	302	Kickdown lever
D1ZF-UA	2100	1.21	351	1971	351	Kickdown lever
D2ZF-FA	2100	1.08	287	1971	302	Kickdown lever
D2ZF-FB	2100	1.08	287	1971	302	Kickdown lever
D3ZF-FA	2100	1.21	351	1973	351	Kickdown lever

All Autolite 2100 and 4100 codes