Small-block

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For other uses of the term, see Small block (disambiguation).

A small-block engine is a North American V8 in a family of engines which generally have a short stroke with less than 6 liters (360 in³) of displacement, although some derivatives have grown larger (up to 427 in³, 7.0 L) (a 505in³, 8.3L V10 is produced by Chrysler, a derative of the LA engines). Larger families of engines are called big-blocks. The distinction came about in the late 1950s when the large full-size cars needed a bigger V8 (with a longer stroke but not necessarily a greater displacement as referenced by Chevy 350 small block and Ford 360 big block) than the smaller mid-size and compact cars - though consumers wanted a V8 under the hood, the recession of the late 1950s provided some of the earliest American awareness of fuel economy. Prior to that point, manufacturers normally had only one V8 engine line.

The term is normally used only for engines from the "Big Three" (Ford Motor Company, General Motors, and Chrysler Corporation) since the other companies did not keep two V8 engine size families. However, it's sometimes used for the more modern and compact V8s produced by others, such as Studebaker.

The term "block" refers to a piston engine cylinder block, which is the lower portion of a piston engine containing the pistons and cylinder bores.

Although a small-block V8 is generally of significantly smaller displacement than the equivalent big-block, a small-block engine can be built to develop significant amounts of power. Additionally, many small-block engines were more advanced technologically than their big-block counterparts, and were much lighter and smaller. Innovations such as aluminum heads and blocks generally came first to small-blocks. From a new car buyer's standpoint, they tended to offer an acceptable compromise between horsepower and economy, so they were a popular option instead of the basic I6 or V6 engine base model. Because of their attractive combination of popularity (and therefore low-cost availability) coupled with good performance, good fuel economy and light weight, they were often preferred in racing and sporting applications. Many hot rods and custom cars are fitted with small-block V8s, particularly the GM (Chevrolet) 350 engine and the Ford 351 Windsor.

There are some cases in which small-blocks seem to encroach upon big-block displacements; in these cases it is most important to keep in mind that small-block and big-block refer to engine families, not simply displacements. For example, engines ranging from the 4.8L Vortec 4800 to the 7.0L LS7 are all GM small block V8s, and share the same general external dimensions. The LS7 achieves enormous displacement by having a very large bore and stroke in the same compact block as previous small-blocks, but has very little space between cylinders. This would not be acceptable in a truck engine, and was not possible forty years ago. As a result, 7.0L is a displacement ordinarily reserved for big-blocks, which can achieve it with fewer compromises in reliability and less engineering effort. A 7.0L big block, like the 427 Chevy first seen in 1966 Corvettes, is a much larger engine externally and shares external dimesions with engines ranging from the 6.5L 396 to the 8.1L Vortec 8100.

Ford

Ford does not categorize its engines using the big/small block nomenclature. Rather, Ford literature distinguishes engine by its series, or family. Enthusiasts unaware of this fine point will nonetheless classify the smaller families as small block engines. Third-party equipment vendors, following suit, have taken up the practice as well.[1]

GM

General Motors small-block V8s include:

Chrysler

Chrysler Corporation small-blocks include:

See also

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