Identifying Dart Heads and Blocks


Dart heads and blocks are stamped or cast with various numbers that can tell you quite a bit about the part.  Knowing how to read and interpret these markings can save a lot of time and hassle when you need to know exactly what you’re working with.

Cylinder Heads – Part Number

Many of our cylinder heads will have a part number stamped on the end, this will be an  eight digit  number in most cases.  In some cases it will be followed by a letter as well.


This number is a standard Dart part number, which can be referenced in a Dart catalog or price guide to determine the configuration of your cylinder heads.  It is useful to note that the part number on Pro 1 heads and Iron Eagle heads may contain the letter “P” at the end if the heads were produced from 2003 to mid 2011.

Cylinder Heads – Intake Volume and Chamber Volume


Often the chamber volume of the cylinder head can be found stamped on the end pad of a Dart head.  This is not always the case, but is frequently so. Additionally, some Dart heads will display the intake runner size on top of the head.

Cylinder Heads – Date Code

One of the numbers you’ll see will be the date code of the cylinder head, which contains information about when the head was manufactured.  This can be in a few formats depending on the age of your heads, since at several points Dart switched date code formats.

The new date code is comprised of three digits, a space, two more digits, another space and then one final digit, as shown below.

The first three digits represent the day out of the total number of days in the year that the part was manufactured on, so the number all three digits form will be in the range of 001 to 365.

The second set of digits are the last two digits of the year the part was manufactured during.  While the last digit represents the shift the part was made on, 1st, 2nd or 3rd.


The older date code used by Dart was a 9 digit code, as in the example below.


In this example the first digit represents the shift, the second and third are the month the part was made during and the fourth and fifth are the day of the month.  The letters CHM are an internal code and the sixth digit is the last digit of the year the part was made.

There are some date codes on very early Dart cylinder heads that predate even this format, these will often consist of three digits that represent the date and then one more digit that represents the shift.

Cylinder Heads – Other Identifiers

The casting number of a Dart cylinder head can generally be found on the top of the head.


This number will begin with the letter DRT on most heads.  Race series aluminum heads will begin with IO, except for Little Chief and Big Chief heads, which will have DRT casting numbers.  Not all Dart heads will have a casting number on them.


Many Dart heads may have a foundry code or a few other identifying numbers cast onto them.  These can be overlooked, as they are generally not useful to the end user for identification.

Some Dart heads will also display a Dart logo.  This can be useful if you are unsure whether your head is a newer design or the earlier model Dart head. The logo on a modern head has thick, stylized lettering, while the earlier heads have narrow lettering.


Race Series Heads

Dart’s Race Series heads will generally have only two stamps on them.  One of those stamps will be the date code, while the other will be a work order number.  The work order number will appear on the end pad of the head, just like the date code does.  With the work order number from your heads, Dart will be able to tell you exactly what specification the head was machined to and if any custom work was done on the head before leaving Dart’s facilities.


At the beginning of 2010 Dart work order numbers were changed to six digit codes that directly referenced a sales order number.  Before that, work order numbers were either five or six digits, with the first two digits being the last numbers of the year in which the head was manufactured, and the remaining digits being the serial number of the head.

Iron Eagle SS Cylinder Heads

The Iron Eagle SS series heads have slightly different markings than other Dart heads.  These heads will bear the casting number 007 on top, and will not usually have part numbers or Dart logos stamped on them.  The best way to identify an Iron Eagle SS head is by the ID code cast on the exhaust face of the head.  This will be a two digit number that can be used to verify that the head in an SS head and to identify the features of the head.


Below is a list of SS head ID codes and what the corresponding characteristics of the head will be with each number.


Engine Blocks – Serial Number

The serial number on a Dart engine block can be found in two places, on the front end of the block…

blockserial1  blockserial2

And on each of the main caps…


The serial number stamped on the front end of the block will be followed by a letter designation that signifies what type of engine block it is.  These letter designations can be read as follows.

LSN – LS Next Iron
– LS Next Aluminum
– LS Next SHP Iron
– LS Next Aluminum Skirted
– Little M
LS – Little M Sportsman
A – SBC Aluminum
I – Iron Eagle
B – Big M
BS – Big M Sportsman
BA – Big M Aluminum
BSA – Big M Sportsman Aluminum
R – Big M Race Series
F – Iron Eagle Ford
FS – Ford Sportsman
FA – Ford Aluminum
FP – Ford SHP
C – CNC Billet
H – Honda

The same number, minus the letter designation will be present on each main cap, followed by the cap number.

Engine Blocks – Casting Number

The bottom side of a Dart engine block will display the casting number of that block.  Dart block casting numbers will begin with the letters DRT or IO.


For additional questions, please call our technical staff at 248-362-1188 (M-F, 9AM – 6PM EST).

This Post Has 22 Comments

  1. Mike smith

    Just bought dart engine DRT-033 with Dart Pro 1 heads the guy said its a 585 but im not positive trying to find what cube block it really is please help.

    1. Jim Brewer

      Mr. Smith, thanks for purchasing Dart Products. Please give our tech line a call with the serial number for the engine. 248-362.1188.

  2. Troy

    For some reason I can’t see the pictures showing how to ID old iron eagle heads vs platinum iron eagle heads. Could u email me pics on how to tell the difference in the 2. Thanks Troy

    1. Jim Brewer

      Hello Troy – this must have been a technical glitch when we created the new site. I’ll work on getting this info to you ASAP. Thanks, Jim.

  3. Cris Traywick

    Is there such a thing as a Dart Pro 1 cast iron (Ford) 351 “Sportsman” block and if so is it 2 or 4 bolt main?

    1. Jim Brewer


      Our 351 sportsman block is machined with billet steel front and rear 2 bolt main caps. The #2,3,4 billet steel center main caps are 4 bolt with splayed outers. Please follow the link below to our product page or visit dartheads.com for more information including the technical specs. We appreciate your interest in our products and services. Thank you!


  4. kevin nolen

    what year is the little M modeled after. parts ordering specify a certain year of block.

    1. Jim Brewer

      It’s the 1955 – 1980 – First Generation SBC – Drivers side dip-stick – standard oil pan rail – 9.025″ deck height.

  5. Glenn

    Hi I have a very early set of sbc dart heads I would like to know the cc they have no assesory bolt holes

    1. Jim Brewer

      Glenn – please give our techline a call at 248-362-1188. Thanks!

      1. Charlie

        Hello I bought a set of heads don’t know what they are there are number stamped on them any way u can tell me what they are so I can buy a intake thanks charlie. First head numbers are 21112chm4 and MP. And 122842 next head has. 1527chm11 and 122842

        1. Jim Brewer

          Charlie – please give our technical staff a call at 248-362-1188. Thank you.

  6. Anders Carlsson

    Hello! my name is Anders Carlsson and I write from Sweden.
    I wonder if there is some information about my 426 Hemi Dart cylinder head. These numbers are available on hedsen.

    02511578 3

    Sincerely Anders Carlsson

    1. Jim Brewer

      Hello Anders,
      We don’t make a hemi head anymore. Is it a billet top fuel head? Also, if your schedule permits, please call 248-362-1188 to speak to one of our technical staff members.
      Thank you!

  7. Anders carlsson

    Hello! My name is Anders Carlsson and I write from sweden.Jag wondering if there is any information about my darts cylinder head that I have on my 1970 Plymouth GTX Hermi 426.Nummer available on cylinderhed are as follows

    02511578 3
    Q048 B6

    Sincerely Anders

  8. matt

    Hi, I need to know which Dart heads I have. The only stamping is in one place it says SB400S 0215
    The other says

    I need to know valve sizes and combustion chamber size. Thank you.

    1. Jim Brewer

      None of the numbers listed identify our cylinder heads.

      There will be a part number stamped on the end of the head where the accessory holes are drilled on the lower left corner.

      Please give our technical staff a call 248-362-1188. Thank you.

  9. Nick Vairo

    I’m trying to identify some heads that are on my car. I have been googling the casting numbers I’ve found but I’m not turning anything up. The numbers I have are DRT007R4093. Any help would be appreciated.

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