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• Ford Block Identification Decoder

The Ford Flathead V-8 engine powered Ford and Mercury vehicles from 1932 to 1954. The Ford Flathead is a valve-in-block engine and the valves open adjacent to the combustion chamber, rather than from the top, as in later engines. The four different V-8 flathead displacement sizes between 1932 and 1953 are 136, 221, 239 and 337 cubic inches.

Step 1

Count the number of studs on the cylinder heads. According to Van Pelt Sales' Ford Flathead Specifications web page, the count is as follows: all 136-cubic-inch engines have 17 studs, all 337-cubic-inch have 24 studs, 1932 to 1937 221-cubic-inch engines have 21 studs, 1938 to 1948 221- and 239-cubic-inch engines have 24 studs. The 1949 to 1953 239- and 255-cubic-inch engines have 24 bolts rather than 24 studs with nuts.

Step 2

Locate the engine serial number. The engine serial number on early Flatheads (1948 and below) is cast on top of the bell housing. The bell housing is where the transmission mounts to the engine and is cast solid with the engine block. On late model flatheads without the bell housing cast into the block (1949-1954), the number is located on the right-rear corner of the intake manifold gasket surface. It is visible with the cylinder heads and manifold on the engine.

Y-BLOCK CASTING NUMBERS. 6015 is Ford's number for an engine block. All blocks have this number. Block identification number generally on side of block above oil. All blocks have this number. Block identification number generally on side of block above oil. The Ford part number on the box shown at left is on the top line: B8A-9431-A. Other information indicates it was an Engine Engineering Division design, weighs 9 pounds, provides information on the quality control inspection, and the date packed. Dec 12, 2010  No, not the casting number but thanks for the info. The one I'm looking for is the vehicle identification number. I'm about to buy a 2000 GT and the seller said the car has a 2004 GT motor in it.

Step 3

Decode the engine serial number. Telusplanet's Ford Flathead V-8 Engine Identification Chart lists 11A as the code for a 1941 V-8. These codes must be referenced to the chart on this site (see References). Engine numbers preceded with a 'C' are Canadian manufactured. On 1948 and later flatheads, Flathead Drag decodes the first letter as the month, the following one or two numbers as the day and final letter as the last digit of the year. G20 B is an engine manufactured on Jan. 20, 1952. The letter code is as follows: M=0, G=1, B=2, L=3, A=4, C=5, K=6, H=7, T=8, R=9, S=10, E=11, F=12.

Measure the stroke. On the 221-, 239- and 255-cubic-inch engine, which cannot be differentiated by any other method, measuring the stroke identifies the engine as they both have different stroke measurements. Remove one of the cylinder heads and crank the engine until one of the pistons is at dead-bottom. Measure the distance between the top of the piston and the top of the cylinder wall with a fine measurement machinist's ruler. The stroke on the 221 measures 3.75 inches, the 239 is 3.1875 inches and the 255 stroke measures 4 inches.

Warning

Ford Block Identification Decoder

• When reassembling the cylinder head after measuring the stroke, be sure to replace the cylinder head gasket and torque the nuts and bolts to the proper specification. The Second Chance Garage website lists the torque as between 65 to 70 foot-lbs.

More Articles

Learn to read the ID tag appropriately. Once you've found the identification tag, you need to know how to read it to get the right information. Luckily, the tags are simple to breakdown. From upper left to bottom right:^[4]

• Cubic Inch Displacement (CID): The first three numbers, found in the upper left corner, tell you the size of the engine.
• Manufacturing Plant: The single letter to the right of the CID is where the engine was built. 'C' is for Cleveland, 'E' is for Ensite, Canada, and 'W' is for Windsor, Canada.
• Year: The next two numbers are for the year the engine was built. 70, for example, would mean it was made in 1970.
• Month Built: This hyphenated number and letter correspond to the month. The months are in alphabetical order, so A = January and M = December. There is no 'i' so people don't confuse it the number 1. 0-A would mean January 1970, 5-C March 1975, etc. (assuming the year code is for the 70's).
• Engine Code Number: This final 3-digit number is the ID of your particular engine. You can look up this code online to see the specs of your current engine.^[5]