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…
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.
L – Little M
LS – Little M Sportsman
A – SBC Aluminum
I – Iron Eagle
P – SHP
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.