Small Block Ford Engine Block Identification

The older 221 and 260 Ford small-blocks are easily identified. According to MRE-Books, these two engines use a five-bolt bell housing and are stamped with the casting code "C2OE" or "C3OE." All Ford small-block casting codes are located on the right side of the engine block just above the starter.

These Ford small-blocks are the most similar, and in some cases, will have the same engine block. Using a variety of identification methods is suggested, as the block casting-code will only give the year of manufacture and other info that does not positively identify the engine. These three engines are the only Ford eight-cylinders that use six bolts on the valve cover. The only absolute way to differentiate these engines from one another is the casting code on the crankshaft, which requires dropping the oil pan, recording the code and matching it with Ford's crankshaft codes.

Ford's 351 "Cleveland" and 351 "M" engines are not to be confused with the 351 "Windsor." Although they have the same displacement, the Cleveland and M variations are members of the 335 family and have notable differences. According to Vintage-Mustang Classics, these engines use smaller, 14-millimeter spark plugs, and the radiator hose does not connect to the intake manifold as it does on the 351 "Windsor." Once again, to differentiate these engines from each other, recording the crankshaft casting number and matching it with Ford's codes is the only absolute identification method.