A “small block” is small and a “big block” is big. If only it were that simple! There is a general relationship to the size of the engine in cubic inches, but there are also enough exceptions to make everything very confusing.
The terms “small block” and “big block” apply predominantly, but not exclusively, to American cars of the 1960s and 1970s. Most of the major auto manufacturers developed two lines of engines, one small and one big. The displacement varied over the years, but the blocks remained basically the same.
For example, Chevrolet “small block” engines had displacements of 265, 283, 302, 305, 307, 327, 350, and 400 cubic inches. Chevrolet “big block” engines had displacements of 396, 402, 409, 427, and 454 cubic inches. You may ask “How could a 400 be a “small block” while a 396 is a “big block?” I told you that it gets confusing. Remember, it has to do with the size of the block, not the displacement of the engine.
Ford engines take the confusion to a new level by not only introducing the term “medium block,” but by offering two completely different engines of the same displacement. Ford “small block” engines include displacements of 260, 289, 302, 351 (Windsor), 351 (Cleveland), and 400 cubic inches. The “medium blocks” include displacements of 390, 427, and 428 cubic inches, but these are often included with the “big blocks” which include displacements of 429 and 460 cubic inches.
Wait… it gets worse. Let’s look at Pontiac engines which include displacements of 301, 326, 350, 389, 400, 428, and 455 cubic inches. Can you guess which ones were “small blocks” and which ones were “big blocks?” This is a trick question because all of these Pontiac engines have the same block. I’m sorry to inform you Trans-Am and GTO owners with 455 CID engines that you do not own a “big block” car.
AMC is similar to Pontiac in that its engines in displacements of 290, 304, 343, 360, 390, and 401 cubic inches are all constructed from the same block. Thus no “big blocks” or “small blocks.”
Mopar (Chrysler) is relatively simple in that “small block” engines include displacements of 273, 318, 340, and 360 cubic inches. “Big block” engines include displacements of 383, 400, 426, and 440 cubic inches.
This list is by no means complete. There are many engine sizes that I did not include due to space limitations and the fact that I was beginning to confuse myself.
The terms “small block” and “big block” apply predominantly, but not exclusively, to American cars of the 1960s and 1970s. Most of the major auto manufacturers developed two lines of engines, one small and one big. The displacement varied over the years, but the blocks remained basically the same.
For example, Chevrolet “small block” engines had displacements of 265, 283, 302, 305, 307, 327, 350, and 400 cubic inches. Chevrolet “big block” engines had displacements of 396, 402, 409, 427, and 454 cubic inches. You may ask “How could a 400 be a “small block” while a 396 is a “big block?” I told you that it gets confusing. Remember, it has to do with the size of the block, not the displacement of the engine.
Ford engines take the confusion to a new level by not only introducing the term “medium block,” but by offering two completely different engines of the same displacement. Ford “small block” engines include displacements of 260, 289, 302, 351 (Windsor), 351 (Cleveland), and 400 cubic inches. The “medium blocks” include displacements of 390, 427, and 428 cubic inches, but these are often included with the “big blocks” which include displacements of 429 and 460 cubic inches.
Wait… it gets worse. Let’s look at Pontiac engines which include displacements of 301, 326, 350, 389, 400, 428, and 455 cubic inches. Can you guess which ones were “small blocks” and which ones were “big blocks?” This is a trick question because all of these Pontiac engines have the same block. I’m sorry to inform you Trans-Am and GTO owners with 455 CID engines that you do not own a “big block” car.
AMC is similar to Pontiac in that its engines in displacements of 290, 304, 343, 360, 390, and 401 cubic inches are all constructed from the same block. Thus no “big blocks” or “small blocks.”
Mopar (Chrysler) is relatively simple in that “small block” engines include displacements of 273, 318, 340, and 360 cubic inches. “Big block” engines include displacements of 383, 400, 426, and 440 cubic inches.
This list is by no means complete. There are many engine sizes that I did not include due to space limitations and the fact that I was beginning to confuse myself.
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