Originally Posted by srt4hokie

I have always wondered what the difference between a big and small block is. I know there is a Chevy 350 small block and a Chevy 350 big block. Also the old 427 was a big block but the new 427 ls7 is a small block so obviously it has nothing to do with displacement.

If I had to take a guess I would say it has to do with stroke and bore. A small block has a smaller actual block so it can’t have that big of a bore and therefore requires a bigger stroke to acquire the same displacement as a big block. The big block has a physically bigger block so it can have a bigger bore and smaller stroke and still achieve the same displacement as a small block with a bigger stroke.

So what is the real difference between the two?