What is the bore and stroke of a 351 Ford?
The bore is 4.00 inches and the stroke is 3.50 inches for Ford's 351 engines. This article explains those dimensions and how they appear across the main 351 variants Ford produced.
Ford’s 351 family includes several variants built over the late 1960s through the 1980s, most notably the Windsor, Cleveland, and M blocks. While there are year-to-year nuances, the basic bore and stroke figures are the starting point for understanding displacement and performance. The sections below break down the primary configurations.
Core 351 dimensions across variants
Below are the standard bore and stroke measurements cited for Ford’s main 351 engines. Note that minor year-to-year tolerances exist, but these figures serve as the commonly referenced baseline.
Ford 351 Windsor (351W)
The Windsor variant became the workhorse throughout the 1960s–1990s for many Ford applications, including performance and daily drivers.
- Bore: 4.000 inches
- Stroke: 3.500 inches
Conclusion: The 351W uses a 4.00" bore and 3.50" stroke, yielding roughly 351 cubic inches of displacement.
Ford 351 Cleveland (351C)
The Cleveland family was introduced in the early 1970s and found in a range of performance-oriented cars and trucks.
- Bore: 4.000 inches
- Stroke: 3.500 inches
Conclusion: The 351C commonly lists a 4.00" bore and 3.50" stroke, producing about 351 cu in of displacement in standard form.
Ford 351M
The 351M was produced in the late 1970s to mid-1980s, bridging certain design elements between Windsor and Cleveland.
- Bore: 4.000 inches
- Stroke: 3.500 inches
Conclusion: The 351M also adheres to the 4.00" bore with a 3.50" stroke in its common configuration, contributing to a 351 cu in displacement.
Summary
Across Ford’s main 351 engine family—Windsor, Cleveland, and M—the standard bore is 4.000 inches and the standard stroke is 3.500 inches, yielding about 351 cubic inches of displacement. While these figures are the baseline and generally consistent, specific models and production years can exhibit minor variations in deck height, valve sizes, or tolerances that may affect exact displacement and performance.
