Exploring Ford’s Powerful 351M V8 Engine: A Deep Dive into the Small-Block Family

The 351M engine, also known as the 5.8L or 351 Cleveland engine, is a member of Ford’s renowned small-block V8 engine family. Produced from 1969 to 1982, this powerplant found its way into a variety of Ford and Mercury vehicles, earning a reputation for its durability and versatility.

The 351M Engine Specifications

The 351M engine boasts a displacement of 351 cubic inches (5.8 liters), with a bore of 4.00 inches and a stroke of 3.50 inches. Its cast-iron block and cylinder heads house a total of 16 valves, with two valves per cylinder, and a single overhead camshaft (SOHC) design.

Specification Measurement
Displacement 351 cubic inches (5.8 liters)
Bore 4.00 inches
Stroke 3.50 inches
Valves 16 (2 per cylinder)
Camshaft Single Overhead Camshaft (SOHC)
Block Material Cast Iron
Head Material Cast Iron

Tuning and Performance Characteristics

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The 351M engine was renowned for its versatility, as it could be tuned to deliver either high torque or high horsepower, depending on the specific configuration. This flexibility was achieved through the use of various carburetor and intake manifold options, as well as different camshaft profiles.

In its stock form, the 351M engine was capable of producing around 265-300 horsepower and 360-400 lb-ft of torque, making it a formidable powerplant for its time.

Aftermarket Modifications and Upgrades

One of the key areas of improvement for the 351M engine is the cylinder heads. Aftermarket aluminum heads can significantly enhance the engine’s efficiency, combustion chamber design, and compression ratio. These upgraded heads typically cost around $700.00 and can be installed with custom spacers and water crossover plumbing.

However, to accommodate the new exhaust ports, custom pushrods and small-block headers may also be required. These additional modifications can further optimize the engine’s performance and unlock its full potential.

Advantages and Disadvantages of the 351M Engine

Advantages:
– Durable and reliable construction
– Versatile tuning capabilities for high torque or high horsepower
– Availability of aftermarket support and upgrades
– Relatively affordable compared to larger displacement engines

Disadvantages:
– Heavier than some other small-block V8 engines due to the cast-iron construction
– May require additional modifications to accommodate aftermarket upgrades
– Older design compared to more modern Ford V8 engines

Applications and Usage

The 351M engine found its way into a variety of Ford and Mercury vehicles during its production run from 1969 to 1982. Some of the notable models that utilized this powerplant include:

  • Ford Mustang II
  • Ford Thunderbird
  • Ford F-Series trucks
  • Mercury Cougar
  • Mercury Marquis

The 351M’s combination of power, durability, and versatility made it a popular choice for both performance enthusiasts and everyday drivers alike.

Conclusion

The 351M engine, part of Ford’s small-block V8 family, is a testament to the automaker’s engineering prowess. With its cast-iron construction, SOHC design, and tuning flexibility, the 351M offered a compelling balance of power and reliability. While it may not be the most modern Ford V8 engine, the 351M’s aftermarket support and upgrade potential make it a compelling choice for those seeking a robust and customizable powerplant.

References:
351M swap
351M Heads for Torque and MPG
Payload Capacity