Date Codes

There are some key attributes about casting date codes and manufacturing codes for engines. For starters all date codes are alphanumeric – containing both letters and numbers.

A ‘casting date code’ provides the exact date when the component was produced at the foundry. A casting date code can be found, for example, at the rear of the engine block, usually above the starter, or between spark plugs on a FE cylinder head. You will notice that the casting date code was actually formed during the casting of the component.

A ‘manufacturing date code’ provides the exact date the assembly took place. Note manufacturing date codes are typically stamped or inked. If the component has undergone machining, it is possible the manufacturing date code may have been removed. As such, it is a good idea to document the manufacturing date code prior to engine work, (e.g.: milling) as this could remove the manufacturing date code forever.

Below is an example of a casting/manufacturing date code:

Casting/Manufacturing date code: 6 B 10

6 = 1966 (Note: You will need to identify the decade via part number on the component first)
B = February
10 = 10th day of the month

First Character = Year within decade (i.e.: 0 – 9)

Second Character = MONTH (see below)
A = JANUARY
B = FEBRUARY
C = MARCH
D = APRIL
E = MAY
F = JUNE
G = JULY
H = AUGUST
J = SEPTEMBER
K = OCTOBER
L = NOVEMBER
M = DECEMBER

(Note: There is no ‘I’ in the month identifier)

Third Character = Day of month