440 Six Pack Intake Manifold Torque Sequence and Specs
Since the 440 Six Pack or Six Barrel used two different intake manifolds, many questions are asked about the torque specs. There are different specs for each one. Let’s examine them.
The 1969 440 Six Pack or 6-BBL aluminum intake manifold bolts are torqued to 25 foot-pounds. The 1970 and 1971 cast iron intake manifold bolts are torqued to 40 foot-pounds.
In addition to the torque specs for the Chrysler and Edelbrock intake manifolds, this article will examine the torque sequence for the bolts. Also, what to do when the torque wrench doesn’t fit on one of the bolts.
440 Six Pack Intake Manifold Torque Specs
As per Edelbrock, the 1969 Aluminum 440 Six Pack or Six Barrel intake manifold bolts are torqued in two steps in sequence to 25 foot-pounds.
As per the Chrysler service manual, the 1970 and 1971 440 cast iron intake manifold bolts are torqued in sequence to 40 foot-pounds.
Chrysler doesn’t specify how many steps should be taken to reach 40 foot-pounds. Most engine builders recommend two steps in sequence.
For each manifold after both steps, it’s good practice to recheck all the bolts. This is to make sure they remained tight or to locate a missed bolt during the tightening sequence.
The 440 Six pack and 440 Six Barrel engines came with different intake manifolds. In 1969 the intake manifold was made of aluminum and manufactured by Edelbrock.
For the remaining years, Chrysler manufactured the exact manifold but made in cast iron.
Even though both manifolds are designed identically, the difference in the material between the two manifolds affects the torque specifications.
440 Six Pack or 440 6-BBL Intake Manifold Torque Sequence
The torque sequence recommended by Edelbrock and Chrysler for the 440 Six Pack or 6-BBL intake manifold starts with the middle bolts and then tightening towards the outside bolts.
The exact sequence is the same for both manifolds.
The diagram below shows the sequence for the 440 Six Pack aluminum intake manifold.
The diagram below shows the sequence for the Chrysler 440 Six Pack cast iron intake manifold.
The Torque Wrench Won’t Fit
The torque wrench will not fit on all the 440 Six Pack intake manifold bolts due to the design of the runners.
The answer is to use a crow’s foot (torque adaptor). They are about two inches long. One end attaches to the wrench and the other end to the intake bolt.
Using a crow’s foot changes the leverage of the wrench increasing the torque. The following formula must be used to avoid over tightening the bolts or cracking the aluminum intake.
Torque Wrench Adaptor Formula
The following is the torque wrench adapter formula:
TA x L / L + A = New torque setting
- TA= The desired torque
- L= The length of the torque wrench (From the center of the handle to the center of the square drive).
- A= The length added after attaching the adaptor. (From the center of the square drive to the center wrench drive/opening).
- New torque setting (This will be lower than the desired torque).
Let’s run this formula through an example. In this example:
- I wish to torque the 440 cast iron intake manifold bolts to 40 ft. lbs (TA).
- I’m using a Snap-on torque wrench measuring 20 inches from the center of the handle to the center of the square drive (L).
- The adapter is 2″ long (A).
Let’s apply the formula:
- 40 (TA) x 20 (L)=800
- 800/20 (L) + 2 (A)
- 800/22=36.3 (New torque setting)
Therefore, I would have to set the torque wrench at 36.3 to achieve my desired torque of 40 foot-pounds.
Don’t want to purchase an adaptor?
- Others will get a feel for the tightness of the torqued bolts and apply that feel to the other bolts which the wrench won’t fit on.
- Borrow an adaptor.
- Many people don’t torque their intake manifold bolts at all.
- I recommend torquing the bolts. A proper seal is essential on an intake.
Check out other intake manifold torque specs here:
Aftermarket Studs or Bolts
Different bolts and the use of studs may change the torque specs used although the sequence would remain the same. Always check with the manufacturer of the bolts or studs for their recommendations.
If you have any questions about the intake manifold torque specs for a 440 Six Pack, send us an email found specifically on our contact page.
For the past 40 years, I’ve been studying and researching Mopar engines including Six Pack intake manifolds. I torqued my first Six Barrel intake manifold 38 years ago while building my first 440 Mopar engine.
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