The Deck Height of a Mopar 440 (Plus How to Measure It)

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

The deck height of a Plymouth or Dodge 440 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 all the years it was produced, from 1966 to 1978.

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 Deck Height

The 440 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.

Mopar 440 Block Deck Height
Mopar 440 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 deck height, rod length, rod journal size, stroke and main journal size:

440 (1966-1978)
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 deck height, connecting rod journal size, main journal size, connecting rod size.

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

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 440 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 cast iron or aluminum decks.

How to use a bore gauge to measure the main journal diameter.

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

Read More Deck Height Articles

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.

Find out how to put Hemi (426) Heads on a 440 in my article, Can You Put Hemi Heads on a 440?

Read More Mopar Engine Articles

440 Firing Order

440 Rod Journal Size

440 Main Bearing Size

Mopar 440 Compression Ratio

440 Engine in Liters

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