Mopar 440 Six Pack Deck Height and How to Measure It

Knowing the Six Pack deck height may help when modifying the engine or doing a stock rebuild. Let’s answer, what is the deck height of a 440 Six pack?

The deck height of a Mopar 440 Six Pack or 6-BBL is 10.725 inches. The deck height is the distance from the centerline of the crankshaft to the deck surface of the block. It is the same for the three years it was produced, from 1969 to 1971.

This article will show you pictures of the block deck height. In addition, I’ll include the connecting rod length, stroke, the rod journal size and the main bearing journal diameter.

440 Six Pack Deck Height

The Plymouth 440 Six Barrel or Dodge 440 Six Pack engine deck height of 10.725 in. is the largest height block of all the common big blocks during the muscle car era.

It shared the engine deck height with the other Chrysler RB blocks (tall deck) and was more than the low deck engines.

The deck height measurement is shown in the photo below.

440 Six Pack or 6-BBL block deck height.
440 Six Pack or 6 BBL block deck height

Deck height can also be described as the distance from the center of the main bearing bore to the flat surface of the block where the cylinder head installs.

The deck or block height of an engine dictates the connecting rod length, crankshaft stroke and the piston compression height.

The following table indicates the 440 Six Pack deck height, rod length, rod journal size, stroke and main journal size:

440 Six Pack/6-BBL
Block Deck Height10.725 in.
Connecting Rod Length (Center to Center)6.768 in. (6.766″-6.770″)
Crankshaft Main Journal Diameter2.75″
Connecting Rod Journal Diameter2.375″
440 Six Pack deck height, connecting rod journal size, main journal size, connecting rod size.

During a standard rebuild of your original, unmolested Six Pack engine, the deck height isn’t a critical measurement.

440 Six Pack/Six Barrel block deck and crankshaft center.
440 Six PackSix Barrel block deck and crankshaft center

If the block was previously rebuilt and the deck surface was shaved (decked), the height is more important. This will affect the piston to deck clearance and the quench.

It’s a bigger concern in higher performance engine builds using stroker cranks, longer connecting rods or custom pistons.

The last thing anyone wants is the top of the piston getting to know the cylinder head by making contact. This may occur with the incorrect piston to deck clearance.

The 1st minute shows what block deck height is.

How is the 440 Six Pack Block Deck Height Measured?

The most accurate and recommended way is to have it measured at a machine shop. All the cylinders should be measured because the height will vary between them.

Home builders will often measure the deck height in the following manner. Using a dial bore gauge and 12″ calipers:

  • Install the main caps without the bearings.
  • Measure the main bearing bore and divide it by 2 to find the radius.
  • Hook the caliper jaw on the main bearing bore.
  • Measure up through the cylinder to the deck surface.
  • Add the caliper measurement to the main bearing bore radius.

Measuring is the same for the 440 Six Pack cast iron or aluminum decks.

440 Six Pack/Six Barrel main bearing bore.
440 Six PackSix Barrel main bearing bore
12" dial calipers to measure from the main journal to the deck surface.
12 dial calipers to measure from the main journal to the deck surface
How to use a bore gauge to measure the main journal diameter.

If you have any 440 Six Pack deck height questions, piston deck or about the post, you may send us an email found on our contact page.

More Deck Height Articles

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426 Hemi Deck Height

I learned about Mopar block deck heights by first building my own 440 engine in 1984. In addition, reading Mopar books, articles, magazines, seminars and watching videos for approximately 40 years.

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440 Six Pack Rod Journal Size

440 Six Pack Firing Order

440 Six Pack Specs

440 Six Pack Compression Ratio

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