How to Identify a Ford 312 Engine

by Floyd Drake III
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57' thunderbird image by Susan Rae Tannenbaum from

First introduced in the 1957 Thunderbird, Ford's 312 c.i.d. V-8 belongs to the Y-Block engine family. According to Ford-Y-Block, the 312 c.i.d. and 292 c.i.d. blocks were identical and used for both engines. All were cast at Ford's Cleveland engine plant for a few short years, making 312 engines highly sought after. In Rod and Custom Magazine's February 009 edition feature article on Y-blocks, parts dealer Bob Carlisle stated, "I must have 50 Y-blocks in house, and only about a dozen are 312s. The 292s are much more plentiful."

Step 1

Locate the block ID number. It is on the side of the block, directly below the cylinder head and above the oil filter. It is nine digits long, containing a four-letter prefix, the generic "6015" Ford block number and a single-letter engineering designation.

Step 2

Decode the number. The letter "E" denotes the 1950s, "C" is for the Cleveland Engine plant. This casting number is shorter than codes found on later engines, and some digits have a different translation than current code listings. According to Precision Engine Tech, most 312s were stamped ECZ-6015-A, B, or C, but these can also be a 292. Any casting number used on 312 blocks were also used on 292 blocks.

Step 3

Identify the engine further to eliminate the 292 engine block. According to Precision Engine Tech, to identify the 312 externally, check the flywheel flange on the crankshaft. The 312 ECZ crankshaft has a small dot on the outer edge. Check the casting number on the main cap if the engine is disassembled. ECZ is cast into 312 main caps; all others are 292 EBU caps.

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