440 Six Pack Idle Speed: Idle and RPM for Auto/Manual Mopar
Many Mopar owners wonder what their 440 Six Pack idle speed or RPM should be set at or what was set by the factory when new.
The following are the 440 Six Pack/Six Barrel idle speeds for each year:
- 1969: 900 RPM (automatic) 1,000 RPM (manual)
- 1970: 900 RPM (automatic or manual)
- 1971: 900 RPM (automatic or manual)
Keep reading for more details about each year. In addition, this article will explain each fast idle RPM for all three or four years. Yes, four years.
440 Six Pack Idle Speed
When the Six Pack was introduced in 1969, the Cleaner Air Package (CAP) and Cleaner Air System (CAS) were already in full swing.
These systems were designed to reduce engine emissions. One of the ways to accomplish this was changing the curb and fast idle speeds.
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 Six Pack’s three year production.
| Year 440 6-Pack/6BBL | IdleSpeed/RPM (Manual) | Idle Speed/RPM (Automatic) |
| 1969 | 1,000 RPM | 900 RPM |
| 1970 | 900 RPM | 900 RPM |
| 1971 | 900 RPM | 900 RPM |
1969 Idle Speed and RPM
Manual Transmission
- Curb Idle Speed: 1,000 RPM
- Fast Idle Speed: 2,200 RPM
Automatic Transmission
- Curb Idle Speed: 900 RPM
- Fast Idle Speed: 1,800 RPM
1970 440 Idle Speed (Six Pack)
Manual Transmission
- Curb Idle Speed: 900 RPM
- Fast Idle Speed (No. 2 Step): 2,200 RPM*
Automatic Transmission
- Curb Idle Speed: 900 RPM
- Fast Idle Speed (No. 2 Step): 1,800 RPM*
* After approximately 500 miles (if necessary)
1971 Idle Speed
Manual Transmission
- Curb Idle Speed: 900 RPM
- Fast Idle Speed (No. 2 Step): 1,800 RPM*
Automatic Transmission
- Curb Idle Speed: 900 RPM
- Fast Idle Speed (No. 2 Step): 1,800 RPM*
* After approximately 500 miles (if necessary)
1972 440 SixPack Idle Speed?
There are three known Six Pack/Six Barrel cars and possibly three or four more that snuck through the factory in 1972.
Learn a lot more about these cars in my article, Cars With a 440 Six Pack From the Factory. Hint: They weren’t in the Cuda or Challenger.
If you’re one of the lucky owners here are the idle specs from the 1972 service manual.
Manual or Automatic Transmission
- Curb Idle Speed: 900 RPM
- Fast Idle Speed: 1,800 RPM (Engine hot and screw on the 2nd highest step of Cam)
More Mopar Engine Idle Articles
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.
Is your 440-6 rich? Check out this video below.
I learned the hard way adjusting the idle speed on my 1970 Six-Pack engine 39 years ago. I had a high-performance cam which increased the idle speed. I’ve been researching Mopars and the Six Packs for approximately 40 years. My research includes personal experience, books, manuals, articles, magazines, webinars, live events and videos.
Read More Mopar Engine Articles!
Article Resources
- Plymouth and Dodge Service Manual: 1969-1972
- Google Books: The Mopar Six Pack Engine Handbook HP1528: How to Rebuild and Modify the 440
- Wikipedia: Chrysler B Engine
- Google Books: Chrysler Engines 1922-1998
