Mopar 440 Idle Speed: Idle and RPM for Automatic or Manual

Many owners wonder what their Mopar 440 idle speed or RPM should be set at or what was set by the factory when new.

The following are the Mopar 440 High-Performance idle speeds for each year:

• 1967: 650 RPM (auto or manual)
• 1968: 650 RPM (auto or manual)
• 1969: 650 RPM (auto) 700 RPM (manual)
• 1970: 800 RPM (auto) 900 RPM (manual)
• 1971: 900 RPM (auto or manual)
• 1972: 900 RPM (auto or manual) 800 (manual/California)
• 1973: 800 RPM (auto or manual)
• 1974: 800 RPM (auto)

The following are the standard Mopar 440 idle speeds for each year:

• 1966: 500 RPM (auto or manual/without CAP)
• 1966: 600 RPM (auto/w CAP) 650 RPM (manual/w CAP)
• 1967: 650 RPM (auto or manual)
• 1968: 550 RPM (auto)
• 1969: 600 RPM (auto)
• 1970: 650 RPM (auto)
• 1971: 750 RPM (auto)
• 1972: 750 RPM (auto) 700 RPM (auto/California)
• 1973: 700 RPM (auto)
• 1974: 750 RPM (auto)

Keep reading for more details and why the RPMs increased over the years. In addition, this article will explain every year’s fast idle RPM, California specs and list the carburetor numbers.

Mopar 440 Idle Speed

Idle speeds have changed over the years due to the Cleaner Air Package (CAP), Cleaner Air System (CAS) and Evaporation Control System (E.C.S.).

These systems were designed to reduce engine emissions. One of the ways to accomplish this was increasing the curb and fast idle speeds.

C.A.S. was introduced first. C.A.P. later became C.A.S. Then E.C.S. was introduced in 1970 for California cars. In 1971 all the Chrysler engines came equipped with C.A.S. and E.C.S.

Obviously if your cam or engine has been modified in any way, these idle specs may not pertain to you. Either way, it’s interesting to see how things were back then and how they changed during the 440 engine’s production.

This article will cover the “muscle car” years, 1966-1974. Both standard and high-performance 440 engines are both included.

440 High-Performance Idle Speed and RPM Specs

1970 Idle Speed: 440 H.P.

Manual Transmission with C.A.S. (AVS-4737S)

• Curb Idle Speed: 900 RPM
• Fast Idle Speed: 2,000 RPM*

Automatic Transmission with C.A.S. (AVS-4738S/Without AC)

• Curb Idle Speed: 800 RPM
• Fast Idle Speed: 1,800 RPM*

Automatic Transmission with C.A.S. (AVS-4741S/With AC)

• Curb Idle Speed: 800 RPM
• Fast Idle Speed: 1,800 RPM*

Manual Transmission with E.C.S. (AVS-4739S)

• Curb Idle Speed: 900 RPM
• Fast Idle Speed: 2,000 RPM*

Automatic Transmission with E.C.S. (AVS-4740S)

• Curb Idle Speed: 800 RPM
• Fast Idle Speed: 1,800 RPM*

* After approximately 500 miles (if necessary)

1971 Idle Speed and RPM Specs

In 1971 all Chrysler cars were equipped with the evaporation control system (E.C.S.). Therefore, there are no differences between CAS and ECS liked in 1970.

Manual Transmission (AVS-4967S)

• Curb Idle Speed: 900 RPM
• Fast Idle Speed: 2,100 RPM*

Automatic Transmission (AVS-4968S)

• Curb Idle Speed: 900 RPM
• Fast Idle Speed: 1,800 RPM*

* After approximately 500 miles (if necessary)

1972 Idle Speed: 440 High-Performance

The following idle specs are for the Holley model 4160 series carburetors.

Automatic Transmission (R-6257A) California Specs

• Curb Idle Speed: 900 RPM
• Fast Idle Speed (2nd Step): 1,800 RPM

1973 Idle Speed: 440 High-Performance

The following idle specs are for the Carter Thermo-Quad carburetors.

Automatic Transmission (TQ-6324S)

• Curb Idle Speed: 800 RPM
• Fast Idle Speed (after 500 miles): 1,700 RPM

Automatic Transmission (TQ-6411S) California Specs

• Curb Idle Speed: 800 RPM
• Fast Idle Speed (after 500 miles): 1,700 RPM

1974 Idle Speed: 440 High-Performance

The following idle specs are for the Carter Thermo-Quad carburetors.

Automatic Transmission (TQ-6462S)

• Curb Idle Speed: 800 RPM
• Fast Idle Speed (after 500 miles): 1,700 RPM

Automatic Transmission (TQ-6463S) California Specs

• Curb Idle Speed: 800 RPM
• Fast Idle Speed (after 500 miles): 1,700 RPM

Other Idle Speed Articles:

• I wrote a separate article for the 6-Pack which you can check out here, 440 Six Pack Idle Speed.
• Find out how the Hemi idle speeds compared in my article 426 Hemi Idle Speed.

440 Idle Speed: Standard Engine

In 1966, the first year of the Mopar 440 engine, there was only a standard 440 without the high-performance engine.

1966 Idle Speed: 440 With CAP

The following idle specs are for the Carter AFB carburetors with the cleaner air package.

Manual Transmission (AFB-4136S)

• Curb Idle Speed: 650 RPM
• Curb Idle Speed (with AC on): 650 RPM
• Fast Idle Speed: 1,500 RPM

Automatic Transmission (AFB-4137S)

• Curb Idle Speed: 600 RPM
• Curb Idle Speed (with AC on): 600 RPM
• Fast Idle Speed: 1,500 RPM

1967 Idle Speed: 440 With CAP

The following idle specs are for the Carter AFB carburetors with the cleaner air package.

Manual Transmission (AFB-4311S)

• Curb Idle Speed: 650 RPM
• Curb Idle Speed (with AC on): 650 RPM
• Fast Idle Speed: 1,400**

Automatic Transmission (AFB-4312S)

• Curb Idle Speed: 650 RPM
• Curb Idle Speed (with AC on): 650 RPM
• Fast Idle Speed: 1,400 RPM**

** Speed set on second highest step of the fast idle cam.

1970 Idle Speed: 440

The following idle specs are for the Holley 4160 4-barrel downdraft carburetor.

Automatic Transmission (R-4366A) C.A.S.

• Curb Idle Speed: 650 RPM
• Fast Idle Speed (No. 2 Step): 1,600 RPM

Automatic Transmission (R-4360A) E.C.S.

• Curb Idle Speed: 650 RPM
• Fast Idle Speed (No. 2 Step): 1,600 RPM

1971 Idle Speed: 440

In 1971 all Chrysler engines came equipped with C.A.S. and E.C.S.

The following idle specs are for the Carter AVS 4-Barrel carburetor.

Automatic Transmission (AVS-4966S)

• Curb Idle Speed: 750 RPM
• Fast Idle Speed: 1,800 RPM*

* After approximately 500 miles (if necessary)

1972 Idle Speed: 440

The following idle specs are for the Holley Model 4160 Series 4-Barrel carburetors.

1973 Idle Speed: 440

The following idle specs are for the Carter Thermo-Quad carburetors.

1974 Idle Speed: 440

The following idle specs are for the Carter Thermo-Quad carburetors.

If you have any questions or if you have more information you’d like to contribute, send us an email found on our contact page.

I learned the hard way adjusting the idle speed on my 440 Six-Pack engine 39 years ago. I had a high-performance cam which increased the idle speed. I’ve been researching Mopars and the 440 engines for approximately 40 years. My research includes personal experience, books, manuals, articles, magazines, webinars, live events and videos.

Read More Mopar Engine Articles!

440 Firing Order

Mopar 440 Compression Ratio (All Years)

Article Resources

• Plymouth, Chrysler and Dodge Service Manuals: 1966-1971
• Wikipedia: Chrysler B Engine
• Google Books: Chrysler Engines 1922-1998
• Google books: The Definitive Plymouth Barracuda and Dodge Challenger Guide: 1970-1974