To make it simple:

The difference between a 350 and a 327 is the bore and stroke. A 327 has a small bore and a short stroke.

To stroke an engine is taking the 3.48" stroke of a 350 and making it 3.75 with longer stroked crank... You can also DESTROKE...A common destroke is 350 crank is a 400 block. This makes 377.

There are some interesting facts about different engines. The 292 I6 has a ton of grunt because it has a 4" stroke. When bored out, it has a bore of a 305 (roughly) and the stroke of a 454...TORQUE!!!