I’ve spent years researching and studying the 440 Six Pack engine. It is one of those engines known by every muscle car lover. This makes people wonder about their specs. Therefore, let’s answer, what are the 440 Six Pack specs?
The 440 Six Pack has 440 cubic inches, a 4.32″ bore and 3.75″ stroke, 390 horsepower @ 4,700 RPM and 490 ft. lbs. of torque @ 3,200 RPM. It has a compression ratio of 10.5:1, 3-2 bbl carburetors, 2.08″ intake valves and 1.74″ exhaust valves. The Six Pack’s cam has a lift of .450″ intake and .458″ exhaust.
This article will examine the engine in more detail. I’ll take a look at the camshaft, intake manifolds, carburetors, crankshaft, connecting rods, cylinder heads and pistons. I’ll also examine the torque specifications, production and casting numbers.
The following 440 Six pack specifications and facts were learned from my personal experience and research, Mopar brochures and engine manuals, webinars, videos, books and articles.
440 Six Pack or 6BBL Specs: 1969-1971
Some people want to know, what is a 440 Six Pack engine? A 440 Six Pack engine is a 440 cubic inch engine made by Chrysler for Dodge muscle cars. It’s called a Six Pack because it has three 2 barrel carburetors.
What is a 440 6BBL engine? A 440 Six Barrel (440 6BBL) engine is a 440 cubic inch engine made by Chrysler for Plymouth muscle cars. It is the exact engine as a Six Pack but Chrysler put them in their Plymouths. The Six Pack and 6BBL have the same specifications. Other than the name, there are no differences.
The engine idled off all three carburetors and as long as you didn’t press down hard on the gas pedal, the engine operated with the center carburetor only.
The outside carburetors are vacuum operated and both of them begin to open when the gas pedal is pressed down hard creating more engine vacuum.
When driving around, the engine is operating with either 2 barrels or 6 barrels, never on 4 barrels.
As an owner of a 6BBL setup on a 440, I can tell you there is nothing more exciting than when the outboard carburetors start to open. It’s like the engine was given performance enhancing drugs and you’ll get pinned back into the seat.
The sound of air rushing into all six barrels, 1,350 cfms, is unmatched by any other street car. Before you know it, you’ll be coming off the gas and standing on the brake pedal because you’ll run out of road pretty fast.
The 440 Six Pack/6BBL was only produced for production cars for the following 3 years:
Rumor is three snuck through in early ’72 but it is not considered a production year for them.
Each year there are some differences between the three with the greatest differences occurring from 1969 to 1970. Therefore, there’s three different 440 Six Pack engines made by Chrysler.
The following table includes all the specifications for the 440 Six Pack/6-BBL Engine:
|440 Six Pack/6BBL Specs|
|Cylinder head material||Cast iron|
|Carburetor||Inline 3X2 bbl (Holley)|
|Horsepower||1969-1970: 390 HP @ 4,700 RPM|
1971: 385 HP @ 4,700 RPM
|Torque||490 Ft. Lbs. @ 3,200 RPM|
|Compression Ratio||1969-1970: 10.5:1|
|Camshaft Specs|| .450″ Intake / .458″ Exhaust|
@ .050 228°/241°
|Cylinder heads||Open combustion chamber|
|Cylinder head valves||2.08″ Intake / 1.74″ Exhaust|
Cylinder numbering (front to rear)
Left Bank: 1-3-5-7
Right bank: 2-4-6-8
|Oil capacity||4 qt oil pan plus 1 qt for oil filter (1969)|
6 qt oil pan plus 1 qt for oil filter (1970-1971)
|Fuel line||5/16″ fuel line|
Let’s start with the three carburetors because, after all, it’s what makes the engine what it is. The three carburetor set up sitting on top of an engine is like staring at gold, people are just mesmerized.
All three carburetors are made by Holley from their 2300 series carburetors. In total there is 1,350 cfms:
- Center carburetor: 350 cfm.
- Front carburetor: 500 cfm.
- Rear carburetor: 500 cfm.
It sounds like a lot of cfms and it is. Although 2 and 4 barrel carburetors are rated differently. Having a Six Pack is not equivalent to having a 1,350 cfm 4 barrel carburetor. It’s approximately equal to a 954 cfm four barrel carb.
Also, all the cfms are not opened fully until the engine revs up higher under heavy throttle. Even under full throttle, all six barrels do not instantly open, but they quickly get there.
Here’s a great video of the carburetor linkage under full throttle. The camera is mounted in the engine compartment pointed directly at the carbs. Great video and many hole shots too!
The outer carbs have linkage bars connected to the middle carburetor. Although the middle carburetor doesn’t open the outer carbs under acceleration, vacuum does.
When the gas pedal is released, the middle carb linkage also closes the outer carbs at the same time. It’s shut down linkage. This can be seen in the video above.
I once had a Six Barrel set up on a 440 but the outer carburetors were mechanical and not operated under vacuum like the factory. They each had accelerator pumps. Think of it as a triple pumper set up.
Under acceleration they opened up directly and fully from mashing the gas pedal to the floor. All six barrels fully opened instantly, making it feel like the car was propelled forward by an unknown force.
The smaller two barrel has a choke mechanism. The gas pedal connects to the throttle linkage on this carburetor.
- Rated at 350 cfm.
- 1.50″ butterflies.
- It has the idle adjustment screw.
- Metering block with removable jets.
- Has an accelerator pump.
- It’s a center hung float.
- Fuel inlet is on the passenger side.
- Rated at 500 cfm each.
- 1.75″ butterflies.
- No choke.
- No ide adjustment screw.
- Has idle mixture screws in the base plate that are plugged.
- No accelerator pump.
- Metering plate with gas passage orifice holes.
- Contain a vacuum diaphragm.
- Center hung float.
- Fuel inlet on the passenger side.
Factory Carburetor Numbers
- 1969 Center automatic: 4392
- 1969 Center manual: 4391
- 1969 Front: 4393
- 1969 Rear: 4394
- 1970 Center automatic: 4145 N95 (Cali. emissions)
- 1970 Center manual: 4144 N95 (Cali. emissions)
- 1970 Front 4175 N95 (Cali. emissions)
- 1970 Rear 4365 N95 (Cali. emissions)
- 1970 Center automatic: 4376
- 1970 Center manual: 4375
- 1970 Front: 4382
- 1970 Rear: 4383
- 1971 Center automatic: 4670
- 1971 Center manual: 4669
- 1971 Front: 4671
- 1971 Rear: 4672
Carburetor Numbers for Holley Replacements
Many Six Packs were rebuilt or replaced over the years. Even an old looking carb may not be original.
From the Holley factory replacement carburetor manual:
- 1969-1970: Center carburetor 4144 O.E. Number 3418550
- 1969-1970: Outboard Carburetor 4365 O.E. Number 3462373
- 1971: Center carburetor: 4670 O.E. Number 3512835
- 1971: Outboard carburetor 4672 O.E. Number 3512837
Chrysler used two different intake manifolds. In 1969, they reached out to Edelbrock and had them produce an aluminum intake manifold.
In 1970 and 1971 Chrysler produced their own cast iron version. Both manifolds have a heat crossover in the middle where engine coolant crosses under the middle carb area.
1969: Edelbrock Aluminum
The aluminum intake manifold is identified by the name Edelbrock located on the right front runner, #1.
It has a part number located between the front and center carburetor.
The part number for a 440 Six Pack Edelbrock intake manifold is:
Also, sometimes located on the right side heat riser is the following: CH6B. The speculation is it stands for Chrysler 6 barrel.
Rumor has it Edelbrock was unable to keep up with the demand. The ’69 1/2 cars were a huge hit and the less expensive cars were more popular than the Hemi.
1970-1971 Chrysler Cast Iron Intake
To keep up with demand, in 1970 and 1971, Chrysler made their own cast iron intake manifold which was identical to the aluminum version.
If you’re unsure, which is which, just pick one up. Believe me the cast iron one is very heavy, 57.4 pounds. The aluminum one is 17 pounds.
I’ve lifted this intake on and off a 440 a few times, some with the engine in the car. It’s definitely a shoulder and back workout, especially with the carbs still bolted on.
Also, the cast iron one has the Pentastar logo between the first and second carburetor and had the following casting numbers:
1970-1971 casting numbers for the cast iron 440 Six Pack/6BBL intake manifolds are:
The ones ending in 275 are earlier casting dates, the 276 manifolds are casted later.
The story is the first cast iron manifolds had a porosity problem. While fixing the casting problem, there are rumors Chrysler used the aluminum Edelbrock to keep the production line moving.
Some ’70 cars have the aluminum, and the owners swear it’s original, but they aren’t the original owner so it’s impossible to know for sure.
I know of some original owners who switched to the aluminum intakes to save weight just after a few years of ownership.
The casting number is located on the left rear of the manifold on the runner for the #6 cylinder.
There is a casting date located on the right front runner, #1, of the manifold.
Connecting Rods and Crankshaft Assembly
Many people have heard about the Six Pack rods and assume all 440 Six Packs came with the rods, but they didn’t.
The first year, 1969, the engines came with the standard 440 engine connecting rods.
In 1970 and 1971, the connecting rods were beefed up across the beams resulting in a heavier, stronger rod.
These rods are called “Six Pack rods” but technically it’s inaccurate to call them that because the ’69 Six Pack didn’t have them and later 440 Magnums also had them.
Rumor has it drivers were revving the motors higher than the regular 440s and were throwing rods out the side of the block.
While the rods were beefier, many people today dislike them because they are too heavy and have the same bolt diameter as the regular 440.
Due to their extra weight, the ’70 and ’71 engines were externally balanced. The engine’s damper contains an eccentric balancing ring while the ’69 engine damper is non weighted.
The balancing ring is .210″ thousandths thick.
The ’69 engine was internally balanced because it contained the lighter, regular 440 connecting rods.
The damper casting number for 1970-1971 440 Six Pack or 6BBL is:
The 1970-1971 Six Pack connecting rods has the following casting number:
The 1969 Six Pack connecting rods have the following casting number:
The compression ratio for the Six Pack/6BBL engines received a bump up to 10.5:1. They also have moly rings.
In 1971 the compression ration dropped to 10.3:1 which reduced the horsepower five to 385 HP. This signaled the beginning of the end for the mighty muscle car engines.
Most manufacturers cut back way more in ’71 but Chrysler did their best in ’71 to keep the Hemi and 6 Pack just the way they were.
It’s nice to know the two best engines were retired with dignity and not a shell of their former selves.
The Six Pack pistons were flat top with 4 valve reliefs.
440 Six Pack Piston Specs:
- Cast flat top with valve reliefs.
- 10.5:1 compression in 1969-1970.
- 10.3:1 compression in 1971.
- Chrome moly rings.
The engines used the same head castings as the 440 engines except for some differences.
The Six Pack heads had the following differences:
- They had chrome valve stems.
- Hemi valve springs were installed.
In 1969-1970 the cylinder head casting number for a Six Pack is the following:
For short, these heads are often called the 906 heads.
In 1971 the cylinder head casting number for a Six Pack is:
For short these heads are often called the 346 heads.
It’s reported by some that a few 906 heads made their way onto early ’71 engines. The 346 heads had essentially the same exhaust ports with a change to the intake ports.
The 906 and 346 heads were both open chamber design.
The valve sizes for a 440 Six Pack/6BBL are:
- 2.08″ intake
- 1.74″ exhaust
They remained the same for each year and were the same size as a regular 440. As stated earlier the valve stems were chrome.
The valve springs used on a Six Pack engine were Hemi valve springs.
The rocker arms pivot on rocker arm shafts. There is one shaft per head. There are spacers between the rockers.
The Six Pack and 6BBL engines used a different camshaft than the 440 but it had the same lift and duration.
The camshaft was a low-taper camshaft which used flat-face tappets (lifters). This enabled some rotation of the lifters in the lifter bore which was to reduce excessive wear and tear on the cam.
There is some differing opinions on the camshaft specs. Chrysler didn’t help when they advertised a larger cam at first then what was actually used.
Many magazine articles back in ’69 also had different specs from one article to the next.
The following camshaft specifications are from the Dodge/Plymouth 1969 and 1970 service manual engine specification sections:
|440 Six Pack/6BBL||.450″ Intake|
|268° Intake/284° Exhaust|
@ .050 228° Intake/241° Exhaust
|Engine||Intake Opens (BTC)||Intake Closes (ABC)||Exhaust Opens (BBC)||Exhaust Closes (ATC)|
|440 Six Pack/6BBL||21°||67°||79°||25°|
The engine has a dual breaker distributor, meaning it has dual points. Two points, instead of one, is much better than a single point distributor in any high performance or racing setup.
Typically, single point distributors are good until about 5,500 RPM. I know one thing. If you have the powerful engine, I’m sure you’ll be revving it past 5,500 RPM more than once.
Even though it doesn’t breath like a Hemi, the tach needle is going to shoot past 5,500. For this reason, Chrysler installed dual point distributors in their higher performance engines.
The stiffer spring load on the dual points is efficient up to 6,000 to 6,500 RPM.
Oil Pan and Capacity
The oil pan and capacity for a Six Pack are the following:
- 1969: 4 quart oil pan plus 1 quart for the filter.
- 1970-1971: 6 quart oil pan plus 1 quart for the filter.
The above numbers are taken directly from the ’69 and ’70-’71 service manuals.
Always verify your oil capacity. Many people claim to have different capacities and discrepancies with their dipsticks. Some people claim to have a 5 quart pan plus one with the filter.
If you ask 5 people about oil capacity, you may get 7 different answers.
The ’70 and ’71 are the same as the Hemi pan.
Windage trays for the Six Pack help keep the oil down in the oil pan and to prevent the oil from splashing around.
These helps keep the oil off of the crankshaft and connecting rods which can steal some horsepower. This is more important at higher RPMs than lower.
How to Identify a 440 Six Pack Block
There are 3 things you can do to help identify a 440 Six Pack/6-BBL block:
- Check the front ID pad.
- Check the casting number.
- Check the engine serial number.
- Check the partial vin number.
A 6 Pack block and a 440 block are identical. The partial vin needs to be matched to an original V code car to verify it as an original 6-BBL engine.
Learn the best way to identify an original Six Pack Engine in my article, How to Identify a 440 Six Pack Engine.
The engine ID pad is located on the front of the block to the right of the distributor. It’s flat and approximately 2″ x 3″. The numbers are stamped in and if it’s painted the numbers may be unreadable.
The ID pad can identify the model year and a high performance block.
Typically, there will be 2 lines. The top line having a letter followed by 440. The letter identifies the model year as follows:
- F 440 – F stands for 1970 and 440 indicates the cubic inch.
The second line will have two numbers identifying the upper engine assembly date, the month and day. The date on a 440 Six pack should be followed by HP.
- 12 7 HP – 12 7 indicates December 7th and HP indicates High Performance.
A letter C on the ID pad indicates a special crankshaft and pistons.
- A Maltese cross on the ID pad will indicate .001″ undersized main bearings. Any numbers following the cross indicate the specific bearings that were undersized.
- An R followed by a number on the ID pad will indicate which connecting rod journals are .001″ undersized.
- A Maltese cross and X indicate the same as above but .010″ undersized bearings.
- The letter A on the ID pad indicates .020″ oversize cylinder bores.
- A diamond symbol on the ID pad indicates all the tappets are oversized by .008″
- The letters O.S. on the ID pad indicate .005″ oversize valve stems.
If the ID pad is blank, it typically indicates a warranty block which replaced the original engine.
The casting number, along with the casting date, can tell you what size block and if the block is correct for the model year of your car.
The 440 Six Pack block has the casting numbers located on the left side (driver side) of the block. They are raised numbers and not stamped into the metal.
The 7 digit casting number for a 440 Six Pack engine or 440 from 1969-1971 is:
The Six Pack/6BBL blocks have the same casting number as any other 440 block.
Along with the casting number, is the casting date of the block in the same area. The casting date indicates the day, month and year.
If the casting date is 11 02 70, it means the block was cast on November 2, 1970. However. this block would be for a 1971 model year car, not a 1970 model.
The casting date year and model year will not always match. Typically, if the block is cast after July, it is intended for use in the next model year.
If the block is cast before July, then the casting year usually matches the model year of the car.
Engine Identification/Serial Number (EIN)
440 blocks have the engine serial numbers stamped on the cylinder block oil pan rail at the left rear corner below the starter opening. They will be facing the ground with the engine installed in the car.
The engine serial number contains 14 characters and digits. The first letter or two indicate the assembly plant. The plant codes are as follows:
- PM or M: Mound Road
- PT or T: Trenton
- MV or MN: Maryland
- W: Windsor
The next three digits or numbers are the cubic inch displacement. For a 440 Six Pack, it would be 440.
The next 4 digits represent the 10,000-day calendar. This indicates the exact date it was built.
The following are the Chrysler 10,000 day calendars for 1969, 1907 and 1971:
The last 4 digits or numbers of the EIN are the daily sequential number of engines built.
Beginning in 1968, a partial VIN are stamped on the engine.
On the passenger side of the block, just above the oil pan will be a long, narrow pad with a series of numbers and letter. They are the last 8 digits of the car’s vin number the engine was installed into.
If the partial VIN matches the VIN number of the car, you have a matching numbers engine to the car.
- The 1st number will indicate the model year.
- The 2nd digit is a letter indicating what plant the car was built.
- The last 6 digits (numbers) indicate the vehicle sequence number at that plant.
In 1969 the engine only had one type of air cleaner which came on the A12 code Road Runners and Super Bees.
The cars had a large open hood scoop which was part of the lift off fiberglass hood. The scoop was open and there was no way to close it off for rain or bad weather.
The special instructions on the air cleaner lid said to close off the hood scoop opening and open the under hood air inlets in the base during sub freezing weather or heavy rain storms.
The base of the large air cleaner is metal, painted black and rectangular. It has a rubber seal which mates to the hood when it is installed.
The air cleaner filter is oval. The lid is also oval and is painted orange to match the color of the engine.
The service manual recommended to inspect and/or clean the air filter after every oil change.
There are a few different air cleaners for these two years starting with the shaker hood scoop. The shaker is a classier scoop which also says this car has plenty of horsepower.
The functional scoop allows air through the left and right vents located in the front. The flaps behind the vents can be open or closed by the driver inside the car with a lever mounted under the dash. The lever is similar to the air vent controls.
Air Grabber/Ramcharger or Twin Scoops
The oval base, air filter and lid was used and sealed to the metal work under the hood. The base was black and the lid was painted orange.
The twin scoops would be seen on the ’70 Super Bee. The Air Grabber/Ramcharger popup scoops would be found on the Road Runners and the ’71 cars.
Then there is the closed air filter which would come on the Rallye hood without scoops. The base, air filter and lid were all oval.
The base was painted black and the lid was orange to match the engine. The base had a shield in the front to protect the air cleaner from elements blown back from the fan.
The shield was also used on some California emission cars for fresh air hoods to reduce noise (California Noise Reduction)
Horsepower and Torque
In 1969 and 1970, the engine was rated at 390 horsepower @ 4,700 RPM and 490 ft. lbs. of torque @ 3,200 RPM.
In 1971 it was rated at 385 horsepower @ 4,700 RPM and 490 ft. lbs. of torque @ 3,200 RPM.
The 5 less horsepower in 1971 was due to the compression change in 1971. The compression was reduced from 10.5:1 to 10.3:1.
In total 13,883 Six pack/6BBL engine cars were produced between 1969 and 1971.
- In 1969 3,319 Six Pack/6BBL engine cars were produced.
- In 1970 9,402 SixPack/6BBL engine cars were produced.
- In 1971 1,162 Six Pack/6BBL engine cars were produced.
Engine Casting Numbers
|440 Six Pack/6-BBL Engine Part||Casting Numbers/Years|
|440 Six Pack/6-BBL Block||2536437 (1969-1971)|
|440 Six Pack/6-BBL Heads||2843906 (1969-1970)|
|440 Six Pack/6-BBL Intake Manifolds||CHRY3412046 (1969 Alumn. Edelbrock)|
2946275 (1970-1971 Early)
2946276 (1970-1971 Later)
|440 Six Pack/6-BBL Connecting Rods||1851535 (1969)|
2951908 (1970-1971 – “Six Pack Rods”)
|Part or Bolt||Torque|
|Main bearing caps||85 ft. lbs.||1/2-13|
|Crankshaft rear bearing seal retainer bolt||30 ft. lbs.||3/8-16|
|Connecting rod nut-plain||45 ft. lbs.||3/8-24|
|Camshaft Lockbolt||35 ft. lbs.||7/16-14|
|Cylinder head bolt||70 ft. lbs.||7/16-14|
|Cylinder head cover stud and nut||40 in.-lbs||1/4-28|
|Distributor clamp bolt||200 in.-lbs/15 ft. lbs.||5/16-18|
|Rocker shaft bracket bolt||25 ft. lbs.||3/8-16|
|Oil pan bolt||200 in.-lbs/15 ft. lbs.||5/16-18|
|Oil pan drain plug||20 ft. lbs.||1/2-20|
|Chain case cover||15 ft. lbs||5/16-18|
|Carburetor to manifold||200 in.-lbs./7 ft. lbs.||5/16-24|
|Intake manifold bolt||40 ft. lbs.||3/8-16|
|Exhaust manifold nut||30 ft. lbs.||3/8-24|
|Crankshaft bolt (Vibration Damper)||135 ft. lbs.||3/4-16|
|Vibration damper pulley bolts||200 in.-lbs. (1969)|
9 ft. lbs. (1970)
|Clutch housing bolt||30 ft.lbs.||3/8-16|
|Flywheel to crankshaft||55 ft. lbs.||7/16-20|
|Flexplate to crankshaft||55 ft. lbs.||7/16-20|
|Flexplate to converter||270 in.-lbs.||5/16-24|
|Flywheel housing to cylinder block bolt||50 ft. lbs.||7/16-14|
|Torque converter housing bolt||30 ft. lbs.||3/8-16|
|Oil pump attaching bolt||35 ft. lbs.||3/8-16|
|Oil pump cover bolt||10 ft. lbs.||5/16-18|
|Fuel pump attaching bolt||30 ft. lbs.||3/8-16|
|Spark plug||30 ft. lbs.||14mm|
|Fan attaching bolt||15-18 ft. lbs.||5/16-18|
|Starter mounting bolt||50 ft. lbs.||7/16-14|
|Water pump to housing bolt|
Water pump housing to cylinder block bolt
|30 ft. lbs.||3/8-16|
How many liters is a 440 Six Pack? A 440 Six Pack or 6 barrel engine is 7.210308190492 liters. To convert cubic inches to liters, multiply the cubic inches by 0.0163870640693.
Any questions or if you have more information you’d like to contribute, send us an email found on our contact page.
Read More 440 Six Pack Articles!
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- Hemmings: Chrysler 440 Six Pack
- Motortrend: 1969 Road Runner – Six barrels, No Waiting
- DodgeGarage: The 1969-1/2 Six Pack Super Bee
- Wikipedia: Chrysler B engine
- Wikipedia: Plymouth Superbird
- Google books: The Definitive Plymouth Barracuda and Dodge Challenger Guide: 1970-1974
- The Mopar Blog: Mopar.com
- GTS: Galen’s Tag Service
- Holley: OE Muscle Car Carburetors