Big block small block

[marilyn35]

Please someone explain the difference between a “big block” and a “small block” for me? What constitutes what? What exactly does it mean?
Sorry I did ask this question in another department, and either I’m asking a dumb question or a boring question cause I got no answers! But I would like to know, as reading about it on the internet provides few decisive answers, and is confusing.

Topic

[Tyler Killgore]

Alright small block and big block are strictly Chevy terms. It was to denote their two engine families at the time. The small block wasn’t changed majorly until the LS family came out. I think the small block chevys are the 265, 283, 302, 307, 327, 350, 400 cubic inch motors. The big blocks are split between the 348/409 engines and 396, 402, 427, and 454.
Now Fords and Mopar never classified their engines as small block/big block. But it is “commonly accepted” that Ford 221, 260, 289, 302, 351W, 351M, and 400 are small blocks. The ford big blocks are the 332, 351C, 352, 360, 390, 406, 410, 427, 428, 429, 460 engines.
I don’t know Mopar engines well but I believe the 273, 318, 340, and 360. The big blocks are the 383, 400, 426’s (all variants) and 440s.

Now you may ask “why are some of the small blocks bigger than the big blocks?” That is because at the time when they came out they were “bigger”. For instance when the 265 came out (way back when) it was definately smaller than the 348 “big block”. But as the years went on (and the muscle car era progressed) strokes of all motors were increased. So yes you can have a 400 cubic inch small block but a 332 cubic inch big block. Like I said it was originally a Chevy numbering system, but they soon screwed themselves up. Ford and Mopar use engine series.

[marilyn35]

Much appreciated, thanks very much!

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