The Ford Y Block 239 Cubic Inch (3.9 L) engine was first introduced by Ford in 1954 as a substitute for the 239 Cubic Inch (3.9 L) Ford Flathead engine. At the time the Ford Y Block 239 was thought of as a significant improvement over the 106HP Flathead, by almost 30HP. As the first Ford OHV V8 engine, the Ford Y Block 239 was named for its distinctive skirting which made the form of the engine look like a “Y.”

The original Y Block 239 included unique parts that weren’t compatible with Ford Y Block engines developed later on. These included a mechanical camshaft and 14 mm sparkplug with a washer that would later be replaced in 1955 by a tapered seat 18 mm spark plug.

The Ford Y Block 239 engine was a Ford production V8 that had a number of features not seen before on V8 engines. These features included full pressure oil filtration, valve guide oil diverters, shaft rocker arms, a single water pump, counterweighted fuel pump concentric, oil trough for timing chain oiling, and staggered oiling at the connecting rods.

In the following years from its debut, designers made some select improvements. In 1956, they added an oil singer at the back of the crankshaft. In 1957, they exchanged the old asbestos rope seals with neoprene rear seals. Then, in 1958 they replaced the cartridge oil filter system with a disposable oil filtering system while upgrading the ignition system and oil pump.

The Ford Y Block 239 Cubic Inch engine was included with Ford trucks from the years 1954 to 1964, Ford cars from 1954 to 1962, and the Ford Thunderbird during years 1955, 1956 and 1957. It was succeeded by the Ford-Edsel (FE) and the Ford Windsor engines.