Autolite 1100 vs 1101 Carburetor: What's the Difference?
, by iFJF Direct, 6 min reading time
Confused between the Autolite 1100 and 1101 carburetor? Learn the key differences in venturi size, engine compatibility, and which one your classic Ford actually needs.
If you own a 1960s Ford with an inline-6 engine, you've probably run into the Autolite 1100 vs 1101 question. They look nearly identical, they bolt to the same intake manifold, and they're often listed interchangeably on eBay and parts sites. But there is a difference — and picking the wrong one can leave you with a carburetor that's undersized for your engine.
In this guide, we'll break down exactly what sets the Autolite 1100 and 1101 apart, which engines each one was designed for, and what to look for when buying a replacement today.
The Short Answer
The Autolite 1100 has a 1.10" venturi and was factory-installed on the 144ci and 170ci inline-6 engines (Falcon, Comet, early Mustang). The Autolite 1101 has a slightly larger 1.20" venturi and was designed for the 200ci inline-6 (later Mustangs, Fairlanes, and trucks).
Both are 1-barrel downdraft carburetors with manual chokes. They share the same mounting flange, the same throttle linkage geometry, and the same fuel inlet configuration. The only functional difference is the venturi bore diameter — 0.10 inches.
Because the 1101 has the larger venturi, it's backward-compatible with 144/170ci engines (though slightly over-carbureted at low RPM). A 1100 on a 200ci engine will work, but you'll leave horsepower on the table — the smaller venturi restricts airflow at wide-open throttle.
Specifications Side-by-Side
| Spec | Autolite 1100 | Autolite 1101 |
|---|---|---|
| Venturi Diameter | 1.10" | 1.20" |
| Throttle Bore | 1.50" | 1.50" |
| Choke Type | Manual (Cable) | Manual (Cable) |
| Barrel Count | 1 | 1 |
| Factory Engine | 144ci / 170ci I6 | 200ci I6 |
| Spark Control Valve | Yes | Yes |
| Fuel Inlet | 5/16" Barb | 5/16" Barb |
| Mounting Flange | 2-Stud | 2-Stud |
Which Engine Has Which?
Autolite 1100 Applications
- 1960–1963 Ford Falcon — 144ci I6
- 1961–1965 Ford Falcon — 170ci I6
- 1962–1965 Mercury Comet — 170ci I6
- 1964½ Mustang — 170ci I6 (base engine)
- 1961–1964 Ford Econoline — 144ci / 170ci I6
Autolite 1101 Applications
- 1965–1967 Ford Mustang — 200ci I6
- 1964–1967 Ford Fairlane — 200ci I6
- 1964–1967 Ford Falcon — 200ci I6 (optional upgrade)
- 1964–1967 Mercury Comet — 200ci I6
- 1963–1964 Ford Econoline Truck — 200ci I6
Practical Buying Advice
If you're shopping for a replacement today, here's the reality: most new aftermarket carburetors sold as "Autolite 1100/1101" are built to the 1101 venturi spec. Manufacturers produce one unit that covers both applications because the larger venturi works on all three engine sizes.
Here's what to check before you buy:
- Is it a complete carburetor or a rebuild kit? Many eBay listings in the $30–$100 range are gasket-and-parts kits, not assembled carbs. A complete new unit typically runs $150–$200.
- Is it pre-tuned? A quality replacement should arrive with the float level and idle mixture pre-set. If you have to rebuild and tune it yourself, you're buying a kit, not a carburetor.
- Does it include the spark control valve? This vacuum-advance component is critical for proper ignition timing on stock distributors. Some budget replacements omit it.
- Manual choke confirmed? 1963–1967 Ford I6 engines all use cable-operated manual chokes. Make sure the carburetor has a manual choke lever — not an automatic (hot-air) choke.
Installation Tips
Swapping an Autolite 1100/1101 is one of the easier carburetor jobs on a classic car:
- Tools needed: 1/2" and 9/16" wrenches, flathead screwdriver, pliers
- Time: 30–45 minutes for a DIY mechanic
- Gaskets: Always use a fresh base gasket — do not reuse the old one
- Torque: Snug the mounting nuts evenly — no more than 15 ft-lbs. Over-tightening warps the base flange and causes vacuum leaks
- Fuel filter: Replace the inline filter during the swap — cheap insurance against debris in your new carb
- Post-install: Cycle the fuel pump, check for leaks at all connections, then start and fine-tune the idle mixture 1/8 turn at a time
Common Questions
Q: Can I put an 1101 on a 170ci engine?
A: Yes — the larger venturi won't hurt anything, and many 170ci owners prefer the slight airflow gain. You may notice a small drop in low-RPM throttle response compared to the correctly-sized 1100.
Q: What about the Autolite 1100 with automatic choke?
A: Some later 1100 variants (1968–1969) used a hot-air automatic choke. These are not directly interchangeable with the manual-choke versions without modifying the choke cable and heat riser plumbing. Stick with manual choke for 1963–1967 applications.
Q: Will an 1100/1101 fit a 289 V8?
A: Absolutely not. V8 engines use the Autolite 2100 (2-barrel) or 4100 (4-barrel). The mounting flange, bore spacing, and throttle linkage are completely different.
Q: How do I identify which one I have?
A: Look at the casting number on the float bowl. The 1100 typically has a tag or stamp reading "C4DF" through "C7DF" series. The 1101 uses "C5DF" through "C8DF" tags. If the tag is missing (common on 50-year-old carbs), measure the venturi with a caliper — 1.10" = 1100, 1.20" = 1101.
Q: What's a fair price for a new replacement?
A: A quality complete carburetor with hardware and gaskets: $150–$200. Rebuild kits: $30–$60. Used cores: $50–$100 (but expect to rebuild). If you see a "new Autolite 1101" for $40, it's almost certainly a rebuild kit, not a complete carburetor.
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Includes mounting gasket, fuel filter, fuel line, and hardware kit.
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