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What is the difference between a 302 and 351?
302 vs 351 Windsor difference: 302 is a 4.00″ bore, 351 is a 4.00″ bore, 302 is a 3.00″ stroke, 351 is a 3.50.
No. It’s not an apples-to-apples comparison. The 302 will be cheaper, sure, but the 351 will give you more cubes and a lower RPM peak torque band. Depending on your goals, that could be what you want, or it may not be.
The 302 is also easier to fit in a Miata than a 351 is. At least with the same bell housing, which you’ll need to keep for the SM transmission.
Piston size is the same, but with a 4.00″ bore, the 302 has more displacement – making it cheaper to build with all else being equal.
The 302 has a shorter stroke and smaller combustion chamber volume, which means higher compression (possible) and higher thermal efficiency (more power per pound of air). The 351’s longer stroke means it makes more torque at lower RPMs at the expense of higher RPM HP.
In general, the 302 will be cheaper and more common.
The 351 will be more expensive and less common.
The two blocks are the same physical size. You can put 351 parts on a 302 and vice versa, with the exception of the crank (throw length) and the firing order.
302 is a 302, and 351W is a 351 Windsor. The only difference between the two, is the bores and strokes. Both are pushrod engines.
A 302 has a bore of 4″ and a stroke of 3″. Bore refers to how wide the cylinders are, and stroke refers to how long the piston travel is.
A 351W has a bore of 4″ and a stroke of 3.5″. This makes it have an engine displacement of roughly 1 cubic inch more per cylinder than a 302 (351 vs 302). Engine displacement is calculated by multiplying the bore by the number of cylinders by the stroke by pi (3.14) by 1/2.
FAQ
How do you tell a 302 from a 351?
The easiest way to tell a 302 from a 351 is by the intake manifold bolt pattern. The 302 has a square, four-bolt pattern, while the 351 has the more common small-block Chevy six-bolt pattern.
The 302 and 351 Windsor are both based on the same architecture, so they look very similar. They share the same 4-inch bore spacing (the distance between the centers of adjacent cylinder bores), and use the same bell housing bolt pattern for mounting automatic transmissions.
The most obvious way to tell them apart is that the block casting number for a 302 is “C60E” while the 351 Windsor is “D0AE.” The cylinder heads on a 302 have open chambers with quench pads in them — flat areas at the top of each piston — while the 351 heads have closed chambers, which means they have no quench pads and burn fuel more efficiently.
How much horsepower does a 351 have?
351 are sold to original equipment manufacturers (OEMs) for use in specialty cars and trucks. Ford stopped producing all of its own engine blocks decades ago, and now relies on outside suppliers such as Navistar to supply all its Ford truck engines, including the 351 Windsor. It generates 285 HP.
Will 302 parts fit a 351?
Some parts are interchangeable between the two engines, but many aren’t. This is due not only to differences in bore size and cylinder heads, but also because crankshafts are different between the Windsor (28 oz.) and Cleveland (50 oz.) motors. In fact, even though they share the same block architecture and the same bell housing bolt pattern as the Ford small block V8 family of engines that includes the 289 and 302, many parts are not interchangeable between engines from different years.
Is a 351 Cleveland better than a 351 Windsor?
Engine displacement does not determine power. It determines torque (Twisting force). This means that a 351w will have more torque than a 302, but not necessarily more horsepower (Since horsepower is calculated by multiplying torque times RPM).
In 1969, Ford replaced the 390-cubic-inch FE with a new 351-cubic-inch Windsor V8. The engine was essentially a small block 302 with a taller deck height to accommodate the longer piston stroke.
The larger displacement and taller deck height meant that 351W engines had different external dimensions than their 302 cousins, including taller valve covers, water pumps and oil pans. However, many components were interchangeable between the two engines (for example, cylinder heads).
It’s easy to tell 302 and 351W engines apart just by looking at them. The 351W has a taller deck height and will always have 8 bolts on each side of the intake manifold — the 302 has only six.
What’s a small block? What’s a big block?
The “big” comes from their size. The big block V8 was introduced in 1958 as a replacement for the Y-block (also known as the flathead) that came before it. The big block is 4.4 inches taller than the small block and 1.6 inches longer than the small block, but it’s also 1 inch wider at 6.5 inches across. This made it perfect for use in large cars, trucks and boats.
The small-block engine was introduced in 1955 as a replacement for the flathead V8 that came before it. The 287ci displacement was introduced first, followed shortly by a 265ci version. Ford wanted to keep their engines under 300ci because they were trying to avoid having to pay a federal luxury tax on vehicles with engines over 300ci displacement in 1955.
Conclusion on 302 vs 351
So which one is better 302 vs 351? Sounds like you have a little more money to spend, so 351 would be the choice. The 302 is a great engine, and very strong. But if you can up the budget a little, then it’s time to go with the 351. The main reason is displacement.
In general, more displacement makes more torque, which means more power down low. So for equal money, a 351 will have more cubes, more low end torque, and a lower RPM peak. A 302 will have the same HP, but a slightly higher tq peak with lower tq numbers. In almost any situation, cubes are better. Unless you can make your goals cheaper with the super-cheap 302
The only other thing I’d consider is how much of a resto you’re doing. If you’re doing everything on this car, then throw in an EFI system so that the 351 is not only pretty good looking (maybe add some chrome valve covers), but it’s also much cleaner burning and less finicky than the carb version (which will probably cost more).
