440 Six Pack Timing Specs: Initial and Advance Degrees
The Six Pack or 6-BBL engine timing is a topic often asked by 440 owners. The following are the 440 Six Pack or 6-BBL timing specs for each year.
- 1969: TDC (manual) 5° BTC (auto) set at idle speed
- 1970: 5° BTC (manual or auto) plus or minus 2 1/2°. Set at curb idle (with C.A.S.)
- 1971: 5° BTC (manual or auto) plus or minus 2 1/2°. Set at curb idle (with C.A.S.)
- 1972: 2.5° BTC (manual or auto) plus or minus 2 1/2°. Set at curb idle
This article will dive more into detail about each year including the factory initial, advanced vacuum, advanced mechanical and total timing. Also, the factory specs from 1972 are included. Yes, 1972.
440 Six Pack Timing Specs
The timing specs in this article are the factory settings. Obviously if your engine has been modified these specs may not pertain to your application.
Even though the Six Pack basically remained the same, the timing specs changed over its production run.
The timing changes are a result of the Cleaner Air Package (C.A.P.) and the Cleaner Air System (C.A.S.). These systems are designed to reduce engine emissions.
Overall timing degrees were lowered to meet emission standards.
Distributor RPM and Degrees vs Engine/Crank
Typically, initial engine timing and total advance timing are expressed in crankshaft degrees read at degree marks on the harmonic balancer.
A potentially confusing part of engine ignition timing is distributor vacuum and centrifugal advance curves are often described in terms of distributor degrees and distributor rpm.
The Chrysler service manual does this as shown below in the photo. The distributor rotates at half the speed of the crankshaft with the engine running.
Therefore, to get the crankshaft degrees or rpm, simply multiply the distributor degrees or rpm by two.
For example, let’s say at idle you set the initial timing to 12° BTDC at the crank/balancer. Let’s also say the distributor has 11 degrees of centrifugal advance. The total advance would be 34° with the advance fully in [(11 x 2) + 12 = 34].
Most stock 6-Packs or 6-BBLs seem to be happy and develop the best horsepower somewhere between 32 and 36 degrees total.
1969 Timing Specs
Timing
- Manual: TDC set at idle speed.
- Auto: 5° BTC set at idle speed.
Contact Gap
- .014″ to .019″
Spark Plug
- J11Y Champion or P- 3-4P Mopar***
- If neither is available use Champion J-10Y.
- Gap: .035″
Firing Order/Rotation
- 18436572/Counter-clockwise
1970 Timing Spec
There are two different timing specs, one for automatics and another for manual transmissions.
Manual Transmission with C.A.S.
Distributor Part No./Prestolite
- 3438314/IBS 4014
Timing
- 5° BTC**
- **Plus or minus 2 1/2°. Set at curb idle.
Advance – Centrifugal (Distributor Degrees @ Distributor RPM)
- 0° to 4.5° @ 650 RPM
- 9° to 11° @ 950 RPM
- 12° to 14° @ 2,400 RPM
Advance – Vacuum (Distributor Degrees @ Inches of Mercury)
- 0° to 3.5° @ 11″
- 9.5° to 12.5° @ 15.5″
Automatic Transmission with C.A.S.
Distributor Part No./Prestolite
- 2875982/IBS 4014D
Timing
- 5° BTC**
- **Plus or minus 2 1/2°. Set at curb idle.
Advance – Centrifugal (Distributor Degrees @ Distributor RPM)
- 0° to 5.3° @ 600 RPM
- 9° to 11° @ 850 RPM
- 12° to 14° @ 2,400 RPM
Advance – Vacuum (Distributor Degrees @ Inches of Mercury)
- 0° to 3.5° @ 11″
- 9.5° to 12.5° @ 15.5″
Manual or Automatic
Contact Gap
- .014″ to .019″
Dwell Angle
- One set points 27° to 32°
- Both set points 37° to 42°
Contact Arm Spring Tension
- 17 to 21.5 oz.
Spark Plug
- J11Y Champion or P- 3-4P Mopar***
- If neither is available use Champion J-10Y.
- Gap: .035″
Firing Order/Rotation
- 18436572/Counter-clockwise
1971 Timing Specifications
There are two different timing specs, one for automatics and another for manual transmissions.
Manual Transmission
Distributor Part No. (Chrysler Built)
- 3438577
Timing
- 5° BTC**
- **Plus or minus 2 1/2°. Set at curb idle.
Advance – Centrifugal (Distributor Degrees @ Distributor RPM)
- 1° to 3° @ 700 RPM
- 4.5° to 6.5° @ 950 RPM
- 4.5° to 6.5° @ 2,200 RPM
Advance – Vacuum (Distributor Degrees @ Inches of Mercury)
- 1° to 4° @ 10.5″
- 7.5° to 10° @ 15″
Automatic Transmission with C.A.S.
Distributor Part No. (Chrysler Built)
- 3438577
Timing
- 5° BTC**
- **Plus or minus 2 1/2°. Set at curb idle.
Advance – Centrifugal (Distributor Degrees @ Distributor RPM)
- 1° to 3° @ 700 RPM
- 4.5° to 6.5° @ 950 RPM
- 4.5° to 6.5° @ 2,200 RPM
Advance – Vacuum (Distributor Degrees @ Inches of Mercury)
- 1° to 4° @ 10.5″
- 7.5° to 10° @ 15″
Manual or Automatic
Contact Gap
- .014″ to .019″
Dwell Angle
- One set points 27° to 32°
- Both set points 37° to 42°
Contact Arm Spring Tension
- 17 to 21.5 oz.
Spark Plug
- J11Y Champion or P- 3-4P Mopar***
- If neither is available use Champion J-10Y.
- Gap: .035″
Firing Order/Rotation
- 18436572/Counter-clockwise
1972 Timing Specifications
A ’72 classic Mopar doesn’t get much love, but maybe this classic should.
Yes, a few 1972 Six Pack/Six Barrel cars snuck out of the factory in 1972. Originally Chrysler planned to continue the Six Pack carb option.
Evidence of this is shown in the 1972 sales brochures and service manuals printed before the option was canceled.
For more details on the 1972 cars check out my article, Cars With a 440 Six Pack From the Factory. I include pictures of the brochures.
If you’re one of the 3 to possibly 6 people out there with one of these cars, here are the timing specs.
This year the distributor is electronic and therefore there are no gap or dwell settings. They are the same for automatic or manual transmissions.
Manual or Auto Transmission
Distributor Type/Part No.
- Electronic/3656353
Timing
- 2.5° BTC**
- **Plus or minus 2 1/2°. Set at curb idle.
Advance – Centrifugal (Distributor Degrees @ Distributor RPM)
- 0° to 3.5° @ 650 RPM
- 8° to 10.5° @ 1,000 RPM
- 8° to 10.5° @ 2,150 RPM
Advance – Vacuum (Distributor Degrees @ Inches of Mercury)
- 1° to 4° @ 10.5″
- 8° to 10.5° @ 15.5″
Spark Plug
- Champion: J11Y
- Gap: .035″
Firing Order/Rotation
- 18436572/Counter-clockwise
If you have any questions about any posts, or if you have more information you’d like to contribute, send us an email found on our contact page.
More Mopar Engine Timing Articles
I first learned about 440 Six-Packs and their timing when I owned a Six Barrel engine 39 years ago. I’ve been researching Mopars and the 440 Six Pack engines 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 Manuals: 1969-1972
- Google Books: The Mopar Six Pack Engine Handbook HP1528: How to Rebuild and Modify the 440
- Google books: The Definitive Plymouth Barracuda and Dodge Challenger Guide: 1970-1974
- Direct Connection: Vintage Muscle
- Wikipedia: Chrysler B Engine
