A brief history of the Ford V8 Flat Head

Ford debuted its first production V8 in 1932. It went into the 1932 Ford Model 18 and Model 40 in 1933. It was a 221ci flat head v8 producing 65hp that gained popularity quickly over the 50hp 4cylinder currently offered. The Model 18 was the first low-price, mass-marketed vehicle to have a V8. The flathead V8 came to an end in the US market in 1953 in the US auto market. Making it onto Ward’s list of 10 best engines of the century.  

The Flat head V8 began with a forged steel crankshaft and casting which was the manufacturing standard at the time. Another important feature was that all 8 cylinders were cast in one engine block. It had been done before but this was the first mass produced V8 to house all 8 cylinders in one Cast Iron block. The flathead V8 crankshaft also utilized 3 main bearings and attached 2 connecting rods to a single crank pin. The short crankshaft proved to be very durable. The camshaft, located in the engine above the crankshaft driven by a spur gear system also driving the distributor and driving the mechanical fuel pump off an additional lobe on the flywheel side. The camshaft also utilized 3 cam shaft bearings and a plastic spur gear for the distributor. The intake fed both banks from the inside of the “V” and the exhaust was routed through the block to 3 ports on each side of the block. The middle cylinders on both sides sharing an exhaust port. Through the design it created higher temperatures in the cylinder block increasing the need for a larger cooling system compared to OHV motors. The compact design and availability of aftermarket parts of the Flat head V8 made it a popular choice for hotrodders later in the years.

Through the years or process improvement and technical advancements the crankshaft was made from Cast steel yielding the same durability as the forged crankshaft while also reducing manufacturing costs of the motor. The use of poured main bearings was replaced in 1936 with replaceable main shell bearings and connecting rod inserts enabled lower costs and required less skill for engine rebuilding. Process improvements with the cooling system and upgrades to the fueling system were consistent with evolution of the flat head to provide better performance and efficiency through the years.

There were 5 different Flathead engines offered by Ford from 1932 to 1953 in the American automotive market.

The 221 was the first production Ford Flat Head.  Starting at 65 hp and ending at 90HP. Relocating the water pumps and moving the inlets to the tops of the cylinder heads. Along with adding additional head bolts to increase durability.

The 239 arrived in 1939, originally designed for Mercury vehicles to provide a more powerful engine it made its way into Fords in 1946. This model had revised versions for car and truck models. Starting at 95hp and ending at 110hp. The 239 received various updates to the cooling system to help with efficiency. The distributor was also repositioned at the end of its run in the US market where it was readily accessible.

 The 136 was a smaller and less powerful flat head originally produced in Ford Europe 1935-36. It only had 60 horsepower. The 136 was introduced in the US in 1937 and wasn’t very popular with consumers due to the 85hp flat head being available. It did find its niche in midget racing after World War II. The 136 was eventually replaced by the 226 straight 6 in 1941 in the US market.

The 255 began production in 1948. Made exclusively for Mercury cars and heavy-duty trucks. Early models produced 110hp hp and 200ft/lbs of torque. By 1953 the motors had received a power increase to 125hp and 218ft/lbs of torque. There was a lot of interchangeability with the for Flat Head V8’s. The crankshaft in this motor was a very popular upgrade ford the Ford 239 Flat Head. Production ended in 1953 for this motor.   

               The 337 was Ford’s largest variant of their Flat Head V8. It was produced for heavy duty/ commercial trucks and eventually found its way into Lincoln passenger cars in 1949 when they could not produce their V12. The 337 Flat head produced 154Hp and 275fl/lbs of torque. This motor was replaced in 1952 with the release of the Y-block V8’s.

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