Ford Small-Block Engine Parts Interchange. George Reid
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Engine Identification Tag Information
Beginning in the 1965 model year, Ford V-8 engines were equipped with identification tags from the factory. This tag includes displacement, model year and month of assembly, and change level. The change level advanced only when a replacement part or upgrade was introduced. One example was when rail-style rocker arms were introduced into production on May 2, 1966, along with pent-roof valvecovers on small-block Ford V-8s. The change level addresses engineering changes, making it easier to identify engines. This was more for Ford’s use than ours.
Beginning in 1965, Ford fitted all of its engines with identification tags, which reveal the engine’s makeup and when it was produced.
Small-block Fords have this tag attached to the intake manifold in front of the carburetor. The Boss 302, 351C, 351M, and 400M have the identification tag attached to the ignition coil at the front of the engine.
About Ford Part Numbers
Ford part and casting numbers can be confusing, especially if you’ve never dealt with them before. There are actually two part-numbering systems. The most common one that applies to engines addressed in this book is 1950–1998. Things changed in 1999 with a new numbering system. Here’s how the 1950–1998 system works:
Typical Ford Part/Casting Number
The PREFIX tells you when the part was originally released for production, what car line it was released for, and what engineering group it came from. The prefix breaks down like this:
First Position (Decade)
B = 1950–1959
C = 1960–1969
D = 1970–1979
E = 1980–1989
F = 1990–1999
Second Position (Year of Decade)
The second position indicates the year the part was released by the Engineering Group for production.
Third Position (Car Line)
A = Ford
D = Falcon
G = Comet, Montego, Cyclone
J = Marine and Industrial
K = Edsel
M = Mercury
O = Fairlane, Torino
S = Thunderbird
T = Ford Truck
V = Lincoln
W = Cougar
Z = Mustang
Fourth Position (Engineering Group)**
If you are talking about a service replacement part, the fourth position means division as follows:
A = Chassis
B = Body
E = Engine
Z = Ford Division
Y = Lincoln-Mercury
X = Original Ford Muscle Parts Program
M = Ford Motorsport SVO or Ford Racing Performance Parts
Basic Part Number
The basic part or casting number is the same whether it is an engineering number or a service number. For example, “9510” is the basic number for all carburetors. A finished engine block is “6015,” as another example. Each engine part receives another basic part number.
Suffix
The SUFFIX indicates the change level. “A” means original status of released part. “B” indicates at least one engineering change. The entire alphabet is used except for the letters “I” and “L,” which could be mistaken for the number “1.” When Ford goes through the entire alphabet, it starts over again at “AA,” “AB,” “AC,” “AD,” and so on.
It is important to understand that part, casting, engineering, and service numbers rarely match each other. The casting number is derived from the actual casting or part, and typically does not match the part, engineering, or service numbers. Unless the casting has been revised, the basic casting number does not change. The number you see on the casting does not match the part number in the Ford Master Parts Catalog. And if the catalog you are using is dated (as most are), expect even more changes in your Ford dealer’s microfiche or computer when it comes to suffixes. When demand for a part falls below a predetermined level, Ford discontinues or “N/Rs” the part. “N/R” means “Not Replaced.”
About Date Codes
Ford makes it easy to identify engine castings because it has three foolproof systems. First is the casting number, which indicates the engineering level. Second is the casting date code, an alphanumeric code that is the exact date the item was cast at the foundry. A foundry logo cast into the piece indicates where it was cast. Finally, unless any machine work has been performed, a manufacturing date code is normally stamped into a machined surface, which confirms when the component was manufactured.
Casting and manufacture date codes look like this:
5A26
5 = 1965
A = January
26 = Day
If this code is cast in, it indicates the date that the component was cast at the foundry. If the date code is stamped or inked, it indicates date of manufacture. When a cylinder block or deck is milled, the stamped manufacture date code is usually lost in the machining process.
* If you are talking about a service replacement part, the fourth position means division as follows:
Ford Basic Part Numbers
Ford Part Numbers 1999–Up
Although this book deals primarily with the vintage Ford part-numbering system, late-model 5.0L parts as well as vintage Ford V-8 parts show up in the new 1999–up Ford part-numbering system. The new system works differently than the old and takes some getting used to. The only real difference is the first four characters in the part number. The rest of it remains much the same.
Here’s how 1999–up Ford part numbers work:
First Position (Model Year)
W