I'm new to building engines for other than stock purposes, so let the jokes fly. As long as somewhere in between somebody can help me out.

When someone says, "Bored .030 or .040 over" what does that mean? Also when someone says the stroke is 4.00 for example, what type of measurement is that?

I know the bore is in the cylinders and the stroke I'm assuming is the piston stroke (but you know where assuming leaves you). I want to get the most out of my engine and before I can do that, I need to learn these things. Thanks for the help!