Ford Engine Block Casting Numbers

Ford’s part number convention generally follows the format of a four digit casting code, followed by a four digit basic part number, which will be “6015” for an engine block, followed by the revision version.

The important digits are the first four and last one, two, or even three digits, in some cases. The numbers are cast into various locations on the block itself, depending on what family of blocks you are referencing, but should be fairly recognizable and usually pretty readable.

Ford Engine Block Numbering Convention

The basic breakdown of the modern numbering convention (1959 and newer):

The first digit is a letter and represents the decade in which the part was designed. A = 1940s, B = 1950s, C = 1960s, D = 1970s, E = 1980s, F = 1990s.

The second digit will be a numeral, and will represent the year within that decade (i.e. C2 = 1962; E7 = 1987).

The third digit is usually another letter, but can also be a numeral in rare cases, and it signifies the vehicle the part was designed for. (i.e. S = Thunderbird; T=Truck).

The fourth digit is the engineering division the part originated from, so most of the fourth digits will be “E” for “Engine” with a few exceptions.

A Note about Ford FE Blocks

A majority of FE blocks have either a ‘352’ or a backwards ‘501’ cast into the front of the block. With the exception of a few hi-performance 428 blocks, most all other FE blocks are identical externally. The only way of differentiating between them, since there are no external markings to tell you what you’ve got, is to measure the stroke:

Simply rotate the crankshaft around until the #1 cylinder is at TDC (top dead center) as indicated at the timing mark. Remove the spark plug and insert a wooden dowel into the cylinder until you hit the top of the piston and make a mark on the dowel. (Use the valve cover lip as a constant reference source.)

Then remove the spark plug from the #4 cylinder (when #1 is TDC, #4 is BDC) and make another mark on the dowel.

Then measure the difference. A 360 has a 3.50″ stroke and a 390 has a 3.78″ stroke.