426 Hemi Head Casting Numbers: Easily Identify Hemi Heads

You may be wondering what that old Hemi cylinder head casting number for sale is or collecting dust in your neighbor’s garage.

The following are the 426 Hemi head casting numbers for the production street and race cylinder heads:

  • 2780559: 426 street Hemi from 1966-1971 (Cast Iron)
  • 2468016: 426 race Hemi for 1964 (Cast Iron/”K”)
  • 2531110: 426 race Hemi for 1965 (Aluminum/”Alcoa”)

The following 426 Hemi head casting numbers are for less common, experimental or revised race cylinder heads:

  • 2488596: 426 race Hemi for 1964 (early production/prototype)
  • 2531695: 426 race Hemi for 1965 (Aluminum/”Alcoa”/Rev B)
  • 2531718: 426 race Hemi (A-148/Nascar)
  • 2945270: 426 race Hemi (D3/Nascar/Cast Iron)
  • 3512015X: 426 race Hemi (D4/Nascar/Cast Iron)
  • 3614433: 426 race Hemi (Aluminum)

Just when you thought all classic Mopar Hemi heads were the same (at least the street heads were). This article will explain some general details about each 426 Hemi head and casting number.

426 Hemi Head Casting Numbers: Intake and Exhaust Valves

The following are the casting numbers for each Hemi cylinder head starting with the most common heads found in the street and race Hemi engines (A864 and A990).

The casting numbers are typically found on the top side of the head, in the middle, closer to the exhaust side.

If the valve covers are still on the heads, the RB-series big-block heads don’t have head casting numbers visible.

The valve cover will have to be removed for identification, but the heads don’t have to be removed from the engine block.

426 Street Hemi: 1966-1971

  • Casting #2780559

The street Hemi casting is cast iron for each year. The valves are the same for each year with 2.25″ intakes and 1.94″ exhausts.

If you have this casting number with an M at the end, it’s a Mopar Performance part manufactured later. This is not an original production generation 2 head.

The -M has the same meaning for an iron or aluminum head.

1964 Race Hemi Cylinder Head: “K” Head (Cast Iron)

  • Casting #2468016

The first race Hemi heads are cast iron and have 2.25″ intakes and 1.94″ exhaust, the same as the street heads.

1965 Race Hemi Cylinder Head (Aluminum)

  • Casting #2531110

The ’65 head had some minor modifications and is cast in aluminum. The valves were slightly reduced to 2.23″ for clearance. The 1.94″ exhaust remained the same.

1964 Race Hemi (Early Production/Prototype)

  • Casting #2488596

The early production heads are also cast iron and have the same size valves as the production head.

1965 Race Hemi Head (Rev B)

  • Casting #2531695

The ’65 rev B heads are aluminum with 2.23″ intake valves and 1.94″ exhaust valves.

426 Race Hemi Heads (A-148/Nascar head “Big Valve”)

  • Casting #2531718

These heads are known as the “big valve” Hemi heads used for Nascar. The intake valves are 2.44″ and the exhaust valves 2.08.”

This test head is made out of cast iron and aluminum. The design didn’t last long.

Comparing the race Hemi K head to the street Hemi head.

426 Race Hemi Heads (D3/Nascar)

  • Casting #2945270

The D heads were alternate race Hemi heads for Nascar designed and experimented with in 1969 and 1970. Changes were made affecting intake and exhaust flow.

Valve angles, diameters and port sizes were modified.

426 Race Hemi Heads (D4/Nascar)

  • Casting #3512015X

Another D head used as an alternate race head.

426 Race Hemi Heads (Aluminum)

  • Casting #3614433

This is one of the heads with two plugs per cylinder.

Learn how the factory recommends torquing the heads in my article, 426 Hemi Head Torque Sequence and Specs.

Other Cylinder Head Casting Number Articles:

Watch the Hemi Heads get swapped with some tips and tricks.

If you have any questions, more cylinder head numbers or more information you’d like to contribute, send us an email found specifically on our contact page

For the past 40 years, I’ve been studying and researching Mopar engines and cylinder heads like the 426 Hemi. I’ve assembled and disassembled its cylinder heads, read books, articles, magazines, watched videos, attended seminars and spoken to other Mopar experts.

How about the Hemi blocks? Check out my article, How to Identify a 426 Hemi Engine.

Search More 426 Hemi Engine Articles!

Hemi Specs

Is a 426 Hemi a Big Block or Small Block

The Difference Between a Street and Race Hemi

426 Max Wedge and a Hemi

Article Resources

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