Ford 351 Windsor Vs Cleveland Vs Modified: What's The Difference?
In the world of classic cars, there's a virtually unlimited supply of numbers thrown around that, if you're not familiar with the nomenclature, can seem absolutely baffling. Engine sizes, differential sizes, gear ratios — it can all get pretty convoluted. Things can get even weirder when there's crossover in the naming scheme. A great example is the Ford 351 cubic-inch V8 engine.
If you're familiar with Ford products, you may have heard the terms "351 Windsor" or "351 Cleveland" thrown around. There's also a variant known as the "351 Modified." They're common to find in Mustang and hot rod swaps throughout the nation, but what does it all mean? What exactly is the difference between these three versions of what one might assume is the same V8 engine? Here's the breakdown on Cleveland vs. Windsor vs. Modified variants of the Ford 351 so you are in the know next time someone brings it up!
Location, location, location
Let's start things simple. The 351 designation in each of these engines signifies the engine's displacement in cubic inches. As the names "Cleveland" and "Windsor" might indicate, the engines' names refer to where they were built.
The 351 Windsor engines were built in Windsor, Ontario, just across the water from Detroit, Michigan. You might be familiar with the Windsor nomenclature because it's also the same platform as the legendary Ford 302 V8. The Windsor plant also built the classic 221, 260, and 289 cubic-inch V8 engines, all of which made their way into iconic Ford models like the Mustang, Fairlane, and Falcon.
The 351 Cleveland was built in Cleveland, Ohio. It's rarer than the 351 Windsor, particularly on the U.S. market, having only been made in America for 5 years. The 351 Cleveland had a beefier crankshaft and better airflow than the Windsor. That, combined with the option of two-barrel or four-barrel cylinder heads, made the 351 Cleveland the preferred choice for high-performance builds. DeTomaso even put the American engine into its deeply cool Pantera supercar.
Seeing a 351 Cleveland swap is fairly common in hot rods and Mustangs because of the engine's power benefits. Both engines share the same bell housing pattern, so the Cleveland is almost a drop-in replacement for a 302 or 351 Windsor.
[Featured image by Stephen Foskett via Wikimedia Commons | Cropped and scaled | CC BY-SA 3.0 Unported]
351 Modified stands on its own
The final example of the 351 lineup is known as the 351M — standing for "Modified" or "Michigan," depending on who you ask. Ford never issued an official clarification. This V8 plant gets its "Modified" moniker from enthusiasts noting its similarity to the big block V8 engines.
The 351M came to be after the discontinuation of the 351 Cleveland. Ford used the 351 Cleveland's 3.5-inch stroke in the 400 cubic-inch V8's engine block to create the same displacement. However, given that it stems from a different engine family, it does not share the same interchangeability of parts that you get with the Windsor and Cleveland engines. Smaller size, a different layout, and a taller deck kept the transmissions and intake manifolds from being cross-compatible with other 351s. If you're looking to swap a classic engine into your project car and you find a cheap 351 Modified, it's going to be a little bit more difficult to make work.